Although there is a statute of limitations it does not apply here. You are correct that a mailing address is only a contact point and not your home. Otherwise those with PO boxes would be living in extremely tight quarters. That aside ypu need to prove the the City where you actually reside. This can be done by spuulying copues of utility bills, drivers license, bank statements, credit card billing statements, rent receipts or agreement , mortgage statement. Basically any documents that prove where you actually live. The more the better as, in this case, bulk helps prove your point. They can audit you for other, more currect years but if you can prove your point they will likely not bother. In the absence of that I would suggest sending a letter attesting that you do not live there and giving your actual address along with a few letters from friends or coworkers who know where you live and have lived. Remember that you need to prove the point that you did not live at your parents in 2005 and 2006. Absent an ability to prove your point I would pay them and start using an address in the community where you actually live.