Conflicting messages from chat representatives

When my bill was doubled, I immediately reached out and spoke with a representative via the chat function. They were very helpful and we got my bill back down to a manageable amount. They made me pay the full amount but assured me I would be given a credit for this. They also explicitly told me that this credit meant my next month's bill would be covered and even a few more dollars into the next month. I even reached out again to confirm this and was told the same thing. Well, the next month rolled around and no credit. When I reached out to ask why I am having to pay the full amount, I was told "there is no credit, we don't know what you're talking about." I understand what this representative meant about prorated fees and auto payments through my checking account. My question is, why would two separate representatives tell me something that was flat out not true according to the third? When I asked the third representative this and even asked what a manager can do, I was told "sorry" and "nothing". 

I'm not surprised that this happened and I do not expect anything to happen from this post. Waste of time.