Double charging a customer on purpose

I wanted to replace my very old (2020) router for the my data package as it was too slow. I called Rain and the agent said she will order a new one for me, and when the new router arrives i must immediately cancel the old one so that im not double charged. In 2 days a new router arrived. Since then i have been trying to cancel the old router package and no one is willing to cancel it, and Rain has started charging me for new routers. can you imagine. Rain was able to give a new route in 2 days but they take ages to cancel an older router because they are benefiting from double debit. Each time i call they say we have left a message on your profile for the cancelling department. The cancelling departments will never contact you (maybe they are on indefinite leave) and Rain continue double charging. This is daylight ******* by companies that offer us services. Who is going to help me.