Lmk if you find one. As far as I can tell, we are waiting for bolt12 or something... Or you'd just need to watch for zaps and then query your wallet with lnbits or something to correlate a zap to a product/account. Zaps alone are not enough for this..

"The zap receipt is not a proof of payment, all it proves is that some nostr user fetched an invoice. The existence of the zap receipt implies the invoice as paid, but it could be a lie given a rogue implementation." -nip57