Poor customer service

What a bad experience. Very very poor customer service. I just need to do a simple thing to change my phone number but i have been struggling talking to the matchine. It is so pointless even to call the call centre as the voice recorder always lie saying that they are experiencing high call volume. How can the be high call volume at 8:00 when they open. I need to use my money in the wallet but i cant because they sending the OTP to my old number