Hey guys, I'm new here

I found some Star Alliance Gold Upgrade services on eBay. Name on ebay is envytravel. He's selling a 1 month upgrade for 40 bucks. His website and his eBay ratings look legit too.
I couldn't find enough information about this kind of upgrades, so I have these questions:

1. Will this work without problems?
2. What are the consequences if the airlines find out that I bought it on eBay? Could my ticket get cancelled or will they just remove the status?

I'm primarily looking for a free checked bag, but a lounge entry would be a nice addition too as I have a long transfer.

Thanks for your answers!