Why would anyone reject payments? Did you want to say refund payments?

I'm no fan of those sites, but you can get a key on G2A for less than half of what you're asking for including the shield thing.

Even though they have a slightly dubious reputation at times, I think most people would sooner take a shot at buying 2 keys from different sellers on there in the hope that 1 would work over 1 from a person who they're not familiar with at all. I don't use G2A, but I'm pretty sure more than half their keys work so it would make more financial sense.

I think it's going to be difficult for you to get this off the ground unless you can offer cheaper prices than you are currently. Still, I'll wish you good luck with it.