Since the 2nd of June, I have not been able to access the 5G card they gave for the router on the router

Since the 2nd of June, I have not been able to access the 5G card they gave for the router on the router. I can use it in a phone, but then only 1 person can access Wi-Fi. I cancelled the month to month contract on the 21st of June, but still I have to pay for the service, as my account was up to date.