No minimum spend required.

As for some online spending not given 5%, do check if they fall into other form of category instead of online.

Payment for utilities and etc would probably fall under other retail and so forth.

If you found a legit reason however, just drop a call to CIMB and they'll probably credit it back the next statement date.

I pay statement balance minus cash rebate amount. Didn't get charged interest. Have been doing this for many months