Bad customer service

So the maintenance people from afhco came to my apartment to repair the bathtub that was not giving me any problems. 2 months later I received an invoice saying that I should pay for the maintenance, I called their customer service because I needed to pay my rent and I didn't understand why I was liable for the maintenance that wasn't ordered by me, I spoke to some guy who told me I should pay my rent and they will sort out the issue fine I paid my rent. 3 weeks later which is today I received an sms stating that my account is in arrears, how? I immediately called and spoke to some guy who didn't tell me his name and there was communication breakdown, guy said to me I should call them back he cannot hear me. Cool, I called back this time I spoke to Nosipho who then told me that I'm liable to pay for the plumbing issues in my apartment? How is it that I'm liable for the plumbing of this apartment? I mean they fixed the plumbing in the bathroom when I had 9 months in this apartment. How is it that I'm the one who is responsible for the damage?