MTN Inability To Resolve Voice Mail Technical Issues.

My voicemail has not been operative for 15 days. When calling my number, the message "number not available" is given. Four visits to the MTN store in Keywest, numerous calls to their call center, six E-Mails and four reference numbers later the service is still not working. Numerous and repetitive ussd codes have been provided, all to no avail. Requests to escalate the problem to someone beyond a call center falls on deaf ears. I am of the opinion that the easiest remedy is to port my number to Vodacom after 25 years with MTN.