Being charged for no services

The app keeps crashing whenever I try to do something. This is my third attempt at writing a post. I was charged $150 dollars for literally no reason. They said I have equipment to return, but can't tell me what. They send me a text with a link telling me to "click on returnable devices" and theres nothing listed. I try contacting an agent through the website and through the app. It either crashes in the middle of conversation or they tell me to return my equipment in person. I can't access my account because it keeps crashing. The one time I did I tried to change the payment method so nothing could potentially overcharge my card and it BLOCKED ME from changing it? Said it was restricted. The payment method? On my own account? And I still dont know what I'm being charged for since I supposedly canceled my services and have no equipment to return according to the app.