Similar thing happened to me with Square. I used their debit card and applied a boost for grocery shopping. This promised some percent discount if I shopped at a grocery store. I did a sizable purchase (>$50) and at checkout withdrew $20 in cashback. Turned out, they had hidden conditions for denying the boost if the transaction involves cashback (no way to know this at all). I contacted support who just gave the templated "can't do anything about it sorry" and they force closed the ticket. I would have accepted if they just applied the promised discount on the grocery portion of the bill (since they can clearly detect the cashback), but this seems beyond their ability to program... and at the consumer's expense?
These big companies power themselves by automation, losing sight of the fact that they should be designed to serve humans, not harvest nickel and dimes off of them. It's so easy for them to profit off of massive scale but they can't find any port of the budget to cover their own programming errors and bugs (as rarely as they do occur)??? It's easy to prosecute companies on egregious scams, but these small programming errors that probably affect a non-trivial amount of customers in small ways probably add up to big scams in scale but fly under the radar.