No help with refund

End of November I upgraded from 4g to 5g but instead of 1 router 2 were delivered to me but I called immediately to complain and was told that the other will be canceled and collected but to my surprise I got billed for 2 instead of one and was still waiting for the collection. I called to complain about the billing but was told they'll get back to me with a refund but till today I haven't been refunded and it seems like I won't be. The router was collected later in April and it was still sealed never opened but I'm shocked that I'm being billed for it while I never used it