How to get CenterPoint to upgrade a gas meter

After installing a pool in my backyard I've spent about a month contacting CenterPoint energy to get an upgraded high-flow meter installed on my property. They always claim they will send me an email with the information within 24h but I never receive any email. I've called them at least 7 times since construction was finished to get them to install the upgraded meter.

Does anyone know a better mechanism to contact CenterPoint beyond their customer service line? The people that work the line are nice, but seem like the best they can do is to "send an email" that does nothing.