I had a Comp Cam do that years ago. I had bought everything from Herb McCandless. I called him and told him what happened. He told me to send him the cam and lifters(in order as run on cam). He warranted the cam/lifters and sent me the newer version of his cam(the .650") that was a 3 bolt set-up, a push rod kit, all gaskets and the timing chain to go with it...FREE!!
He would have replaced the valves, but I told him that they were stock valves and I had plenty of them. He also told me later that after he got mine, he got 3 more calls with the same problem. He told me he would not sell any more single bolt cams again!! You might call your part supplier and see if they will give you any help.