Not happy at all, 4 months later and still no refund

They charged me twice in a month because they themselves can't explain how their system works when you take a month-to-month contract for a router. The home premium used to say we used more than the fair usage and we must upgrade. Only to find that upgrade means cancel the current, and be offline for 21 days, then only you can open a new contract. I decided to cancel while getting a new one and their system cannot differentiate the 2, but can charge for both in the same month