Bad service, poor customer management and poor attitude by account department and management

PEC have been estimating my water readings since I moved to my place in April 2017. They would send sms to remind us (the complex) on the reading dates so we can leave our gates opened. I have been leaving my gate open on the dates and I also have a full time person who stays home. I then enquired and asked them why they are not coming to take readings and they told me the gates are always locked...I have been paying around R250 for water only. In September, they finally came to take readings and said I owe them R3500 and they want it IMMEDIATELY. I was surprised and they explained that that was the actual reading and I told them I do not have that kind of cash and can make arrangements. I spoke to different people including the manager who said they cannot make arrangements with me as they want their money. I told him we can arrange to pay at least in 3 months since it is their fault to estimate so low and also not taking readings. Finally he agreed verbally on the phone. I paid in September and October and it was fine. In November, the account lady called me and say I need to pay the outstanding R495 or she will cut my water. She only gave me 1 day to sort it out. I told her It was their fault and I have made arrangements. She starting shouting at me and giving me bad attitude. I dropped the phone.