I would consider this chain to be trashed. Yes it can be resharpened but with a significantly shorter overall life. I would expect the business owner to make good on what has happened to your chain and your wasted time. You don't need to show him that it won't cut. He should have new chains for sale. If he balks compare the teeth on those new ones to what he did to yours. I would approach him with you expecting a new chain and settle for half price for a new chain.At best I can only do a half-assed job sharpening my own chains so once in a blue moon I treat myself by dropping a few chains off at the local power equipment dealer for (hopefully) a better job. This last batch I took to a place I've never used but was assured their tech has a machine he uses. I picked them up today and was putting one back on a bar when the tooth just didn't look right. All the teeth on 3 chains are like this - mostly squared off, no undercut area underneath the top of the cutter. Is this what I should expect?
I have seen some shops farm out the sharpening. Regardless of whose incompetence it was the owner is responsible.