Rebuilding Your Credit

[mishabear]

I have an old lingering debt I would like to deal with but I had problems with my first attempt.  I had an initial debt of under $4000 that went to collections.  In 2002, I lost my job, wife, home, etc...hard times. About 18 month ago, they found me and told me I owe about $11K (three times the original debt?). I made a deal with them and paid $4000 and was to pay another $1800 and call it good.  When I went to pay the $1800, they said I owed TWO more payments. I contested it but they insisted. I tried to talk to higher ups and got nowhere. I asked for a recording of our deal and got nothing. I said "screw it" and planned to just let it roll off, which it will shortly.  

Now I am trying to buy a house and it's coming back to haunt me. They say I owe $7200. I don't contest that I owe them something but 3 times the original debt seems awfully high for such a short period. And it irks me that they would reneg on the deal we made. Can I contest it if I paid something on it already? What can I do to get this unscrupulous anchor off my neck?

Thanks.

[BungalowMo]

You said it was due to fall off "shortly"...how shortly?

[mishabear]

About a year to 18 months.  Not sure exactly.  Credit report is at home.