Just before Christmas I realised it would be simpler, and cheaper, if I upgraded all four of our family’s Tesco Mobile numbers into one account. However, almost immediately all the mobiles stopped working. Callers were told our numbers were invalid, and we couldn’t receive texts, calls or data. I reported the problem immediately but despite making almost 30 calls over the past four weeks, our phones still don’t work. I have been told that a change of systems has affected a number of customers. I don’t care about that; I just want a working phone again. We don’t realise how much we rely on mobiles until they are gone. Online banking and two-factor authentication relies on receiving texts. I am at my wits’ end. JH, Manchester We get very few complaints about Tesco Mobile, and its customer service is generally excellent, so your experience is somewhat surprising. As you say, so much of modern life is built around the mobile phone, so I can see why you were so frustrated after almost a month without one. Happily, within three days of me asking Tesco HQ to intervene, your service was restored. The company has apologised and offered you an undisclosed offer of compensation, and a gesture of goodwill. We welcome letters but cannot answer individually. Email us at consumer.champions@theguardian.com or write to Consumer Champions, Money, the Guardian, 90 York Way, London N1 9GU. Please include a daytime phone number. Submission and publication of all letters is subject to our terms and conditions: http://theguardian.com/letters-terms