Ok so my employer messed up my w4 for 2015 and they put single allowances "2" which really has messed up my refund its suppose to be single allowances "0" how do i fix?

Sorry it's too late to fix 2015.  You can give your employer a new W4 now going forward.  If they didn't take out the right amount for 2015 you can't change it.  What's done is done.  You owe it now.

You should have noticed on your paychecks they weren't taking enough out.

ive called this IRS on the situation and they told me i need to do amended 2015 w-4  which would correct error made on the previous w4

What?  Either you misunderstood them or they misunderstood you.  You can not go back and have your employer take out any more from your paychecks for 2015.  2015 is over.    You give the employer a W4 to tell him how much to withhold.  If you fill out a new W4 it will only be for right now for the future.

You make an "amended" W-4 to correct withholding from the time you submit the W-4 on - for the future. It is not retroactive.

What was withheld for 2015 cannot be changed - it is what it is.   Your tax due (or refund ) is your tax liability minus your withholding (right amount or not).  If the withholding was more than the tax liability, you get a refund, if less, you owe additional tax.

Next year (this year 2016) keep track of your pay stubs and  the amount of withholding and talk to your employer if it is incorrect. You are responsible for paying the tax, and making sure the correct amount was withheld even if the employer made an error.  That is what pay-stubs are for - for you to review and alert your employer to any errors - not to wait until the year is over and done with when it can no longer be corrected.

Get a hold of the hr payroll department and ask for a corrected w-2

problem is it was set that way all year till i noticed last week when i received a paystub in the mail because they switching companies and notice it said my allowances were at 2 when it should have been 0 now its saying im getting a extremely low refund, so didnt even file yet till i get this mess sorted out.

They have to fix it if you didn't claim a dependent they have to show proof that you did if not they have to change it

so just talk to my payroll and they when send out a new w2 with correct numbers because right now im rather upset with what i saw i was getting back and i know that low of an amount is not right.

There is nothing to "fix".    "Withholding" is money that you earn that is kept back "withheld" that you do not get in your pocket.  It is sent to the IRS instead, as an "advance" to pay your estimated tax.

If not enough was withheld, then you received that money in your paycheck and in your pocket instead of being sent to the government - now you have to give it back - same money, you did not loose anything.

Ideally, at years end you neither owe additional tax or receive a refund, which means you neither paid too much or too little in tax during the year.  

A large refund means that you gave the government too much during the year (a interest free loan to the government) and now they have to pay it back.

I understand trust me but you said you never claimed dependent so technically that Money belongs to you and they have to do something call the irs and explain the situation

You "claim" a dependent on your tax return.   You put an "exemption" on a W-4 - different things.   All that does is lower the amount of withholding and puts the money in your paycheck rather than sending it to the government.  

Certainly, the money belongs to her/him, and she/he already received it in the pay check.  Nothing is lost.  That is how it should work.   

You should neither owe additional or get a refund if the exemptions are adjusted properly.  Those that get large refunds have too many exemptions and have given the government a interest free loan during the year rather than having use of their own money during the year.

So either The employer or IRS or both need to give out a tax bracket to the employee not everybody’s a tax genius and every year is different every tax deductions credits etc. change of jobs so yeah actually it is IRS and employer This is why the employer takes out the taxes that’s part of their responsibility. Because if not then why do they even have to fill out a W-4 form to begin with to give to the employer we as an employee would Just do all the handling’s through IRS an employee should just do that and work it with the IRS not the employer  To note employers responsibility once again W 4 form for 2020 has definitely changed and Once again the employer hasto tell the employee by February 15 of 2020that’s not the employees fault or responsibility I think your word usage to answering questions is very disrespectful

@aaron-mcahan that is the stupidest answer that an IRS agent could ever give. It's too late to fix a w-4 from 2015

Spot on!!

Why are you posting to a thread that is 4 years old?   The 6/4/2019 date on everything tells you this thread was migrated from the old system last year.