If you think your SIM card may be faulty, follow these simple steps to see if they help: Remove your SIM card from your phone and clean it with a dry cloth before putting it back in Register your handset to a different network by doing a manual network search. You’ll get an error message. As soon as you see it, register back to TalkTalk Try your SIM in a different phone if you can. If this fixes the problem, then the fault is probably in the phone, rather than the SIM If none of this works, you may need a new SIM. To order one, please contact us.