REO Agent submitted other offer after bank accepted mine

[John H.]

I made an offer on a property listed on MLS through a realtor. The realtor called 2 days later and said the offer was accepted. I told the Realtor I was out of town until late friday, and she said I could get the P&S in on monday. I filled out the paperwork on Monday with my lawyer and submitted it. Tuesday she called and said my proof of funds isn't acceptable and I need another copy. (cash offer). A few hours later, she called and said the bank rejected the P&S because it wasn't signed by Sunday the 15th. I signed it on Monday like we discussed. She said there is a new offer on the property now and I need to submit my second highest and best offer. After hours of lengthy heated discussions she basically said, I'm screwed and I don't need to file a grievance with the board of Realtor's because she isn't even a member, so im out of luck.

I ended up throwing a few grand onto my offer, but I guess i'll have to find another.

Any Advice?