urgent can they take house back w/written agreement

i live in AZ. i signed a written, signed, and notarized agreement/disclaimer to take over payments on a house. when i was able to qualify for a loan they would then sell/sign over the house to me. in the event of non-payment on my behalf they would take financial responsibility back. the payments at that time were six months behind, the house was trashed. since then i have invested money and time in repair of the house. my payments have been late but never to the point of foreclosure. well now they want the house back. what are my rights. do i need an attorney?
thank you
sue

[HomeGuru]

Hire the attorney that you should have used before you first did the deal.