Bulk Services Department - Need Wall Mounted Boxes Updated to HD?

My parents recently moved to a retirement community. The community has Comcast Bulk Service. The two wall mounted Xfinity boxes in their apartment are not capable of HD output. I called in and talked with Brittany in the Comcast Bulk Service department. She was in the process of setting up an new account at my parents address and signing up for HD services at $9.95/month. She indicated she would schedule for a Comcast service person to come out and replace the two wall mounted Xfinity boxes with ones that can output HD signal at no charge. When I was on the phone with Brittany I did not have the serial numbers of the boxes. She was going to call me back that evening when I was at my parents apartment so I could give her the serial numbers and we could finish setting up the account and get the service call to have the boxes switch scheduled. I did not get a call back that evening. Since then my attempts to get back in touch with Brittany have been futile as no one will transfer me to her or give me her phone number. Please advise how a close this loop and get this handled. Thanks in advance!