Prorated Refund after discontinuing service?

[Bob11117]

When I cancelled my late father's landline service, there was still about a week left until the end of our billing period. The CSA with whom I spoke suggested that the bill would be prorated* -- the problem was, my brother, who is dad's executor and bill-payer, had sent in a check for the full amount of the bill. Where can I verify that the amount of the bill was adjusted, and therefrom the amount of the refund and when it will be sent?

*Note: When I tried to use the Ask Verizon feature, it complained that I was reportedly using profanity; the only unusual word I used therein was the one marked with the asterisk, which the last time I looked is not commonly regarded as vulgar or profane.