I just paid using TNB website itself. If payment through unifi TM website counts as online payment I don't see why this shouldn't. It's better than shopee in that I know it is paying towards my electric account (you can just register online). Some shopee seller gives discount for TNB credit purchase but shopee website won't transact the deal after keying like ten times the same card details etc.. Finally gave up and upon examining my TNB bill, it does say one can pay via its webpage!!
Hope this helps.

just a call away to have peaceful days ahead 

next time, try not to do it TOO early or too exact at 12:00:00am    your system time may not be same as bank's system time or merchant's system time.

even if everything resides locally in malaysia, there could be few minutes off across all parties (you vs merchant/payment gateway vs bank).

i always call bank directly to query the date, time, or MCC if i have doubt. they are checking directly from the system, so it's accurate.

No la.. i tunggu until 12:05 Thats why I mentioned was weird - TM OTP update sudah at 12:00 or 12:01. But until 12:10 lidat Maxis Pay OTP screen (paid 2nd) still bo update to next day. But when pay, the email notification instant and updated (but from Maxis portal).

Time difference also not quite likely unless server is outside Msia? Spore also same time zone bah.. Takkan server dekat Bangladesh pulak hahaha.. I'll give them a ring after tomorrow then.