Experian and TransUnion Dispute

I have repeatedly disputed a collection account with Midland Credit Management since February 2009 when I found it listed on my credit reports, In May 2010 one of their customer No-service representatives had told me they had nothing from the original creditor ( Aspire Visa ) they could provide me with? I contacted Aspire Card Services (aka Aspire Visa) asking them to provide me with proof of the account they told me they couldn't because they could “NOT” find a account in there system with my name, ssn, and dob? I contacted Midland Credit Management again and told them what Aspire told me and I asked them to contact Aspire and verify the account with them. Midland Credit Management refused to do so claiming “they never contact the original creditors, and the account was purchased from a third party not from Aspire Visa” and refused to remove it from my credit reports. Soon after this I noticed it was updated on my reports showing my first delinquency as being April of 2010 (re aging the account I NEVER paid one cent on BECAUSE IT IS NOT MINE!!!) I disputed this with Experian, Equifax, and TransUnion. So far Equifax is the only one to delete this from my report. This account that isn't mine is still damaging my Experian and TransUnion reports any ideas on what I can do at this point to remove it from Experian and TransUnion? I am looking at buying a home soon and even tho my Credit Union said it can approve me for a home loan with my current score, why should I pay a higher interest rate on my loan, because of a debt that is not mine?