This is frustrating and have had a similar situation happen to me. I purchased a "custom" .264 Win Mag off of Gunbroker and the seller had good feedback (Zero issues reported). Rifle arrived and I put a round in the mag to check it out, cycled the round out of the mag and the bolt would not close. Tried another round, same thing. I noticed a slight movement with the barrel and it was loose. The goober had just screwed the barrel into the action all the way and hand tightened the barrel nut. Needless to say that I was very upset as his description said it was custom made by his gunsmith. I was able to borrow some GO/NO-GO Gauges to install the barrel correctly and it shoots very well.
I hope you get the issues resolved and it is good to know the identity of the seller as these are not just simple mistakes or oversights that were missed with the sale ad.
I hope you get the issues resolved and it is good to know the identity of the seller as these are not just simple mistakes or oversights that were missed with the sale ad.