Two things that has to be straigthened regarding this as they're rather crucial points; One, as I said on the very early part of this discussion, they're not scamming anyone. There's no money lost since your fund was sent back to you, and two, they're not trying to buy you. The way I see it [and I think most who reads it does too] it's some kind of token of appreciation for pointing out the bugs. They don't have to pay you any, but they choose to do so. Likewise, you're not obligated to receive it, but you're free to do so if you give the list of the bugs you discovered.