There is a problem about MNP that is the TAC from banks sometimes is not received by the user who switched from different telco but keeping the same number. Below is the solution:
[Maybank2u]
1. You need to call the customer service center at 1300886688 and tell them that you have switched to different telco but keeping the same number.
[CIMB]
1. Call 1300880900 for CIMB customer care and do the same above.
Actually, if you don’t do anything, the system (Maybank2u or CIMBClicks) will automatically change to you new telco in about a week. But if you want it to be faster, just call the number.
Hope that helps!