Is anyone or their DH a plumber? If so, can you please FM me....

As per our contract on our new home, the sellers were supposed to get the shutoff valves in the kitchen replaced. At walkthrough they showed the realtor and my DH that there were shiny new valves under the sink and replaced piping.

The super came up to us yesterday (we're in a co-op) and said 'if you're putting $ into the kitchen, you need to change the shutoff valves..." "no, the sellers had them fixed" "no, I fixed them...and they're not good".... so the super admits that they're no good.... we go to try them and sure enough, there are shiny new handles, but they don't shut the water off!

We need a written estimate from a licensed plumber to get this fixed. No one will give me a written estimate base they're saying it's a job that's less than $1000, so they just come out and do the job for aprox $450. I need the estimate though so that I can get the money from their escrow. Does anyone know of a plumber who would give an estimate on their letterhead for a small job?