Money deducted from my account by clientele even though my account is not in arrears

I really depressed by the greed being displayed by this company. I have a policy with then and an agreement that they must deduct fees from my account at the end of every month. They deducted the fees from my account as per agreement but still saw it proper to go and then deduct more money from my account during the middle of the month. I was shocked after going to a filling station and pouring petrol only for my card to get declined afterwards. There I was then with no cash in hand and a bill to settle with no cash in hand. I called clientele and they told me that the reason that they deducted the monies from my account is because they track my account and found I had money and that I should be happy coz the atleast they won't deduct any monies from me at the end of the month. I am still trying to figure out what right they had to go into my account especially given that my account with them is up to date. When demanding my money, they told me that I should call my bank and reverse the funds. My bank charges a bank fee for reversals so now I must from my own pocket pay for the airtime that I used to call clientele as well as the reversal fee. When I told them that I am not gonna do that they then told me that there claims department closes at 12 and that they will only process my claim the following day and it might take a few days for the monies to reflect in my account. Its pathetic that we still have companies that put profits before people, that bank on the fact that people don't complain because its always a very lengthy drawn out process and because people don't check their bank statements. I really regret doing business with such people and companies, and in a just and fair world such companies would not exist (or atleast so I hope)