Hathway — No refund provided after disconnection & continuous spam calls everyday

I have raised a request and paid the money to Hathway to relocate my connection to a different place within the city. They have told the resolution time is 48 hours. I waited for 2 weeks and called them multiple times, but there was no response from them. Hence I switched my connection to a different provider and raised an another request to close my account. They took their sweet time of 1 month to collect the router from me. It has been 3 months since and I still did not receive the refund. On top of that, I have been getting multiple calls everyday from Hathaway customer support to recharge my account. Even after explaining the situation multiple times, they have not stopped calling and if we ask why do we even get the calls even after explaining so many times they will cut the call not even bothered to listen..

Please assist on this.