Hallo nikkib and welcome,
Please make sure you are logging into the Business Class Portal (BCP) using your Administrator account, then follow these instructions to make a payment . Also, please be advised that if you are 60ish plus days past due, then you will have a temporary all services interruption and this could possibly be the root cause of your mysterious payment processing activity on the BCP. Just call in to 1-800-391-3000 Option 2 and any Comcast Billing Agent will be able to provide you direct assistance.
Hope this helps you out.