Unable to Cancel Rain 5G

I have started my service with Rain 5G on the 3rd of May 2022. The internet service was extremely bad. I contacted them a few times but they were not able to assist. I managed to successfully cancel it on the 6th of May 2022. Since then I have contacted Rain 7 times to arrange pick up of the router and to get my refund. They keep telling me that the Billing department will contact me as they cannot transfer me to them. It is now the 19th of May 2022 and still no one has gotten back to me. This is absolutely ridiculous as I cannot use the service but they refuse to help me get my refund and pick up their router.