What to do.

I have a very nice 1936-S Walking Liberty Half Dollar. It looks completely original to me and has beautiful mint luster. I sent it to NGC for grading many months ago and it was returned in their famous body bag as having a "Reverse Wheel Mark". I was sending in another group of coins for grading and decided to send it again. This time it comes back as "Improperly cleaned". Is their any way to win in this environment? I will send the coin to PCGS and hope that I can get an honest answer. Does anyone have similar problems?