how to get a refund for a cancelled service

Thank you so much for taking the time to reach out to Comcast Business Support here on our Community Forum @user_6b38b8!  We are so glad to hear from you and want to help in any way that we can to address your billing concerns.  Generally when an account is closed with a credit balance, that amount is sent to the address on file in the form of a paper check 30 days after receipt if the final bill.