We got a letter from IRS stating we owe $2000+ which is strange we are simply workers and I filled all questions related to W2. What could have caused this error?

1) Read the letter, which likely explains Why you owe, and for which Year. For IRS guidance on understanding, see https://www.irs.gov/individuals/understanding-your-irs-notice-or-letter 

2) Post back here with your findings, and someone in this forum may have further ideas. 

3) To contact TT Live Support (one-on-one help, which you’re apparently paying for) :

https://ttlc.intuit.com/community/expert-review/help/how-do-i-connect-with-a-tax-expert-in-turbotax-live/00/27282

Did it say anything about  you claimed excess Social Security?

Are you married and filed Joint?  And you both had W2s?  The IRS is probably right.  They usually are in this case.  You assigned both spouse's W2 to the same person so it looked like that person went over the max.

For 2018.  Do you still have copies of all the W2s?  Look at box 4.  Did either of you have more than 1 employer?  You only get excess SS back if one person had more than 1 employer and those employers took out more than the max of  $7,960.80.  So add up your W2 box 4.  Is it more?  Then add up your spouse's W2 box 4.  Is their box 4 more than $7,960.80?

Or check W2 box 12.  You may have entered Code A by mistake.