American Home Mortgage Real Time Resolutions Questionable foreclosure, collection account on 2nd mortgage Irvine, Texas

I had a foreclosure on my home in August of 2007.  I had a piggyback loan 80/20, both mortgages were serviced by Option One.  I attempted a loan modification and even had an investor interested in purchasing my home.  While I was awaiting the results of my modification response, US Bank showed up on the deed (I learned this by doing an internet search).  I received a letter days before my foreclosure date that the loan modification on both loans was denied due to "property sold".  My home was foreclosed on.  There was a small surplus (about $8000) from the first mortgage, but $0 was applied to the second.  Since this time I have been contacted by Option One, FASLO Solutions, an attorney for FASLO Solutions, American Home Mortgage, Real Time Resolutions, and an attorney for Real Time Resolutions (who also owns the company I found out) to collect on the full 2nd mortgage balance.  I had attempted to negotiate with FASLO, but they refused to send me a written repayment agreement, stopped contacting me, and then I started receiving calls from Real Time (December 2008) on behalf of American Home Mortgage.  I informed the caller I never had a mortgage with this company and was working with another agency, and to please provide me proof in writing that this is my debt in order to receive a response from me.  I did not provide this in writing then.  I have received some invoices and privacy notices from them over the past couple years, and a few calls a week.  I have never received validation of this debt.  Now they are reporting on my Experian credit report.  I have sent a certified debt validation request letter to them and have disputed the account on my credit report.  If anyone has any suggestions as to how I can further handle this situation to stop the calls and get my credit cleaned up, I would greatly appreciate it.  I do not have the money to pay a retainer to an attorney.  These practices seem unethical and perhaps illegal.  There has been a lot of press lately about illegal foreclosures and document forgery, so I'm pretty nervous about the type of company/companies I'm forced to deal with.