Is MTN *****ing money ********ly?

Can someone at MTN please tell me who authorised the activation of CallerTunez on my account? It almost seems like MTN is *******ly activating paid subscription services on my account that will cost me something without my athorisation, so MTN is *******ly *****ing my money....hopefully this is not the case?

Are these sms's I received really from MTN, and if it is, would you deactivate it as I DID NOT AUTHORISE THIS:

Received from *** (CallerTunez):

Message 1 - received 01.07.19 @ 08h27: Y'ello. Your MTN CallerTunez subscription was successfully renewed at R0.50 for 7 Days. To cancel dial *155#. Ts&Cs www.mtn.co.za. Reminder:

Message 2 - received 06.07.19 @ 15h15: Y'ello. Your Subscription service to MTN CallerTunez will expire on 2019-07-07 and will be renewed at R0.50/wk. To cancel dial *155#.

Message 3 - received 08.07.19 @ 19h19: Y'ello. Your MTN CallerTunez subscription was successfully renewed at R0.50 for 7 Days. To cancel dial *155#. Ts&Cs www.mtn.co.za.

I am hoping my concern is unfounded, but also actually hoping this is indeed from MTN, as I've dialed the *155# number which simply leads to a declaration that nothing is activated, so hopefully this is not some **** attempt but actually a number from MTN, but if it is, please deactivate.