What you do really depends on how much energy you want to invest in trying to get a resolution. By all means take it to resolution and state your claim there as succinctly and non emotively as you have done here detailing what steps you have taken to try and work out a resolution with the vendor. Alternatively you can leave the review you think the vendor deserves for this transaction and walk away and buy from someone else in future. If I had one bad experience with a vendor who wasn't interested in working out a resolution I would not be using them again but that's just me.