See my opinion about this here:
Not trying to defend them or anything, but I want to write about my experience with this issue.
I remember in one PM I had with the Coinpaycard forum rep after I experienced this issue (for the 3rd time), he told me that the banking API they use would credit those funds which were loaded, but the website itself has an error and would not show the updated balance.
Each time, this happened when loading the card from the account balance, not when refilling the account balance itself.
One time (and this happened some time around Feb 1st) my balance was showing some really small amount, like $4 or something after I loaded about $60 or $70, but meanwhile my OpenAI payment was successfully processed during this time. I got invoiced, but the card statement was out-of-date.
First two times he actually manually updated my balance to fix the problem. But it is a highly annoying process, and I'm still waiting for him to do it again or to fix the site's API to credit $220 I added a few days ago.
The customer support pages were always unresponsive the whole time - I only got answers via forum PM.