Could u recall that... Did OCBC side? or Maybe those Merchant side did previously give u 'warning' before on ur these transactions? Either a obvious email/call warning or maybe in-app notification. If yes, then maybe they treat it as - warning issued, customer no obey, report & block! Like xander83 say, maybe is the merchant(s) that is the one that reported, only bank open file to check into ur account. And since u r not a big customer to them (as more like u r earning the rewards from them rather than giving them business), so they rather just lose u this customer rather than going through a big round of AMLA process.

Dont think BNM will side u, since bank did not do anything against the policies (they just lack of humanity, which is not against the law).


Btw, maybe ur request to increased Credit Card limit is the Reg Flag event that trigger such whole case. The bank have been compromising to ur spending habit (which in fact already a bit over), but they just let it go on since nth happen. But as u requested higher limit, means there will be even higher transactions in future, which is much more higher than the average spending pattern for such an income...