Broken Oral Agreement, fraud, or misrepresentation?

2 years ago I co-signed for my aunt and uncle for them to buy a house. Earlier this year, I found out the house was foreclosed and was on my credit report (I never lived in the house). I was ured that I was only signing as a co-signer, but now Washington Mutual (where the mortgage was loaned) is saying I am a primary (there are 3 primary signers-- me, my aunt, and my uncle). I ordered the signed paperwork for the loan from Washinton Mutual and I did indeed sign as a primary, but I was just signing where the realtor told me to sign. When I call the realtor and my aunt and uncle now, they all tell me that I was only supposed to be a co-signer (and both groups try to blame each other claiming they do not know what is going on). Is this grounds to take any of them to court for breaking an oral agreement, misrepresentation, or fraud?