After you file

I have a question, I owed $5900 in taxes and I was suppose to get back over $7000 thousand this year, and they send me my bill stating you owe $5914.00 for all previous tax years owed and listed on the back of the letter for me to see, and today I get a letter stating they applied my refund $2458.00 to a previous year, which is a LIE. I am holding the letter stating I owed $5914 on March 15th, I was suppose to get back like $8000.00, but it would be $2459 after the IRS took their portion and someone how they took that too, and now I do not owe anyone else, they claimed to have applied it  2007 taxes, which was made out of my total refund of $8000 dollars...I am pissed and I cannot wait to call them tomorrow.