Worst service ever, I had to drive to another branch

I have 3 contracts with MTN and I decided to go cancel, one router, because it hasn't been working I called MTN several time with no success, I router was even switched off by default by MTN that's what one consultant said, so I called to cancel and I was told to go to the store, But the treatment received was on another level pathetic, rude, unprofessional, terrible and heartbreaking the lady that was helping me was absolutely horrible, rude and laughing/mocking me, when I asked one of the other staff where's the manager, the manager was actually standing right next to the lady who was rude all the time since my arrival and when I asked the manager so you standing right next to her and allowing this to go on all along in your presence and the manager responded with so much attitude screamed and said to me I can't hear anything and I never saw her laughing at you! Yet they literally standing shoulder to shoulder, then the lady takes my box and slammed it on the other side of the counter telling me she (The manager) will help you know imagine after standing there for over 20 minutes and filled in cancelation forms, I took my box and went to another store is this treatment right from staff and the manager does absolutely nothing?

So the staff at Woodmead Mtn branch do as they please with customers knowing that the manager will back them up no matter what, I don't know why people like this get jobs honestly!