MTN removes my SIM off the Network when it still had airtime

Today I woke up and my MTN SIM was off the Network. I then asked their Twitter support via DM why my SIM was not connecting. I was told that it was because I had not make a charged call in 90 days. I then asked why I was not told about this 90 day rule when I bought the SIM and loaded airtime that I was told I will not be reimbursed for? I was not given an answer. This is bad customer service as I have been with MTN for years. I proceeded to ask why I was not warned via sms a few days before that my number was in danger of being taken and given to another user if I do not make a call and that all my airtime would be forfeited and I was not given an answer. This is bad and unfair customer service from MTN. These are things that as customers we need to be told when we buy SIM cards so that we can play by rules that we know about. This was such a bad experience for me. I was told that I will not be getting that phone number back as it is now owned by another customer. I was advised to go buy another SIM get a new phone number, then rebuy the airtime and just move along. Unempathetically as if they don't know how hard we work for that money to buy these SIM cards and airtime.