We take our customers' security very seriously. We may block calls and stop certain telephone numbers calling our customers if we have concerns they may be spam or nuisance calls. We're also required by law to block invalid telephone numbers that you cannot call. If you've tried to call one of our customers on more than one occasion and think you've been incorrectly blocked, get in touch with us at CLIQuery@talktalkplc.com. We'll need you to tell us the number you were trying to dial and why you think your number should not be blocked. We'll then investigate and let you know the outcome. Any personal data you provide will only be used to resolve the query. To find out more about how we process and protect personal data, please view our privacy policy.