MTN- Bad service

I purchased a new simcard from a MTN outled in Vredenburg ZA approx 2 weeks ago. The number *** has been registered to the sim. All was working well witout any problems. Whatapp has been activated to this number after OTP has been received. The 071 number have been registered with all financial institusions and with my clients. Then my number has been changed to another number by MTN without my knowledge or concent that caused a magor problem on my side. I have been visiting the MTN outlets at ipic center. , Vredenburg and West coast Mall, Vredenburg but without any positive reponse to retreave my number. I have been sitting witouth my number for almost a week. My only current means of communication via my 071 number is whatsapp. The 135 customer care number has also been called and they do not even understand the problem.. This problem has not been caused by myself and currently MTN cannot assist in fixing it...