Never trust these guys to hold up on their end on the bargain

Every month I earn substantial amounts back via healthy food. I know the process and I had been following the steps for a few months.

Then, for May I almost got nothing back. I repeatedly queried this but was told that I must be at fault. I provided proof with bank transactions. Still, not enough. The transactions did not pull through on their end so I must have made an error. They need slips. I mean, who the hell keeps slips to fight a big company who are supposed to have their house in order.

What a load of ****. The nerve to blame it on me after following the process correctly for months!

In fact, most months I have a dispute with these guys because they don't want to pay up and make "accidental errors" and eventually they do.

Surely it can't be that difficult to offer your core business correctly at least 50% of the time??

See attached bank transaction list and screenshot of (mostly) consistent cashbacks and the change in May