How many times can an app purchase be refunded on Play Store?
Paid apps/games!/in-app purchases can only be refunded once. If you buy the app again, you can't get refund
From Play Store help (see
Refunds &amp; returns → Learn about refunds on Google Play →Google Play refund policies)

Note: You can only return an app or game for a refund once. If you buy it again you will not be able to get a refund. If a refund is issued you will lose access to the item.

(Emphasis added)
Related: If a paid app stops working, can I get my money back?