How long is too long before requesting a refund

[axen4211]

I bought a peice of medical equipment. The seller stated that it looked like it had not been used. I got it for a really good price but, apon the first chance I got on its arrival, it gave an error. 

I tried to work with the local vendor to see if it could be repaired of refurbished but, after a lot of back and forth, all they wanted to do is sell me a new one. Which is way out of our buget at this time.

I contacted the seller to see if I could work with them in some way. Maybe, they had it checked out before selling it and it was damaged in shipping or maybe, they knew of a company I could turn to for repair of refurbishing. I have recieved no responce from the seller at all.

What can I do.