I'm sorry to say but the preset's cannot be refunded. This is due to the fact that once bought, you already own and have access to the file and that cannot be taken if one was to refund.

Purchasing my preset's is a choice, if you like how it sounds and you are willing to buy then go for it. I think my preset's stand out from other creator's as I also am an artist who used to use preset's (I now mix).