Product: Debt or credit management

On XX/XX/XXXX, I noticed my credit report was attacked by this company GLA collections. 
I received a letter from these tyrants 3 months ago that stated the insurance company didn't cover my XXXX removal procedure and therefore, I had to pay the bill. Pretty frustrating, and although I do not agree with that answer, I decided to pay off this {$4000.00} bill. I gave this company GLA {$700.00} worth of payment over the last 3 months. Isn't that good? Most people that have bills in collections, do not pay them, but here I am paying the bill. I did not give this company any problems. I paid it a few months and was going to continue paying the bill until it was complete. BUT starting yesterday, this company attacked my credit stating I owe like {$2300.00}. WHY would a company that you are making payments to ever attack you? 
So I called and got a rude lady on the phone. She told me she didn't care about my XXXX and didn't want to hear me whine about it. I told her I was not whining, but letting her know why that bill was not paid in XXXX. She was so rude, I hung up and called back to ask for the general manager or owner of the company. Then they put a guy on the phone who says he was a manager. I asked for the GM, but they refused to get him on the phone. I told this gentleman they need to remove this from my credit report ASAP as I have made payments and was going to continue making them. He said, you should have called the office and not made payments online. I told him the letter GLA mailed me said to make payments online or call. So I made payments. SO how can you attack me when I did what the letter stated? He said, well in 90 days from the letter, we put it on your credit report. I told him that was unfair and he should repay me for the {$700.00} I already paid. If they are going to ruin my credit, then I want my funds back that I already paid. They are not getting a XXXX out of me. I do not see how consumer protection and the fair credit reporting act allows companies like this to destroy American families by attacking their credit as a means to force someone to pay them in FULL, when that family is making honest payments to the company. 
This mgr told me you could have paid this bill from XXXX until now, so it needs to be paid. Very rude coming from a guy who works at a collections company and just got the bill on his desk 3 months ago. I have been paying GLA since they received the bill, so how they are not grateful I am making payments is beyond me. You'd think they would appreciate me making {$700.00} payments in XXXX months. 
I told them I will not pay this in full. He said then we can not remove it. He said if you can make payments, we will remove it AFTER it is paid off. 
I can not trust this company to do that and I will not let this sit on my report when I did not do anything to earn this bill to begin with. This bill should not even be mine. But I am paying it. 
I told the manager I will make payments, IF you remove this from my report. If I don't pay as promised, THEN you put it on my credit report, but he was rude as well and said no we will just destroy your credit. Real classy people. They need to be penalized for this unethical behavior. I was making payments and doing just fine with this bill, but it wasn't good enough? They could have asked me to pay more or called to let me know it was going on my credit. ANYTHING but attack my credit!!!!!