the same thing happened to me when i paid 7 sat/byte but opted into RBF. because i paid with an RBF transaction, bitrefill didn't allow for instant processing. the same rationale apparently applies to transactions with unconfirmed parents.
this is inconvenient compared to their normal process but it certainly isn't a scam.
Looking from different perspective, they don't mention about relation between RBF / CPFP and 0-conf whether on payment or FAQ page.this is inconvenient compared to their normal process but it certainly isn't a scam.
It'd be better if they explicitly mention whether they accept 0-conf if the transaction have RBF flag or uses CPFP.
i agree, it would be nice if they mentioned it with fine print on the payment page, or linked to a separate payment troubleshooting page that explains these things. i mentioned something to that effect to support at the time.
like the OP, i was pretty annoyed since i ended up having to wait a half day or so for confirmation, but i took it as a lesson learned---i didn't start throwing around scam accusations.
words of wisdom from satoshi still apply today:
As you figured out, the root problem is we shouldn't be counting or spending transactions until they have at least 1 confirmation. 0/unconfirmed transactions are very much second class citizens. At most, they are advice that something has been received, but counting them as balance or spending them is premature.
We will see if it's worth to include this requirement detail together with the minimum fee and no RBF.
this would help.