My apologies for this inconvenience. I am more than glad to extend a helping hand. Firstly, I would have you remove the SIM card and re-insert it. Most if not all SIM cards nowadays can only be inserted one way. I don’t think it’s the positioning of the SIM card itself but it’s always good to check.
Secondly, I would have you do a network reset. This will entail going into your device settings and depending on the phone that you are using, the process might be slightly different but in theory, it’s all the same. After you have accessed settings, locate either ‘General’ for iPhones or ‘General Management’ for Samsung devices. Then scroll to where it says ‘reset’. Under ‘reset’ there should be an option to do a ‘network reset’.
If you’ve already tried these options, make sure you are logged into the forum and you can send me a private message by clicking on my name ‘ComcastChrisL’ and then click on ‘send message’. Make sure to include first and last name of account holder, full address or account number, and last 4 digits of the stored payment method on file. Also include the cell number of the device you are having issues with.