Customer service continuously lies to me

I have been on the chat and phone multiple times for multiple hours trying to get my billing corrected. The first time they said they would extend my plan by 24 months and said they had already implemented the changes. A couple weeks go by and my bills are still incorrect. So I reached out again and was able to get on the phone with someone who said they were going to reach out to someone else in the company see how to get the bill corrected. Another week went by and again I went on chat to get this corrected. After a long time of getting redirected back and forth to literally the same agents they told me that they were able to implement the same plan I had previously, the same one that they originally told me they had already done now a month prior. It is now a couple weeks later and I have once again been charged way more than my previous plan. So my question is how many times are you allowed to lie to me?