You can get technical support for AT&T U-verse at ATT.com. Contact information and hours of operation can be found in the support section of the website.
From the ATT.com home page, click the support link in the header of the page. This takes you to the AT&T support center, which allows you to choose the service for which you need technical support. From here, you can click the call us link found in the upper-right corner of the page.
Click the link that represents the appropriate service type. This will populate a list of contact numbers, including technical support, from which you can choose.