Contract signed and not honored

[Nlybarge]

Ok so heres my problem... I was trying to sell my car and found an aquintance who was willing to buy. However she needed time to find her own financing. So we agreed she could make a few of my payments untill then. I drew up a contract stating she is financially and liably responsible for the car. Well now it turns out she took the car and drove it to the east coast (im in washington state). She states the payments have been made, however the financing company is calling saying its two payments over due. she won't cooperate in giving me a bank statement or something proving she's paid. and she also won't pay to have it shipped back west. I was wondering if it is possible to report it stolen? any and all help to get me out of this mess is appreciated.