iPhone owners who have holidayed abroad this summer have returned to costly bills caused by roaming charges which many were not expecting.
The charges have been accumulated by those who have accessed data networks while abroad and various UK network providers have been hit with complaints by customers who had endeavoured to deactivate any data services when roaming.
Some of the worst-hit cases saw consumers facing charges of almost £1,500, despite disabling roaming before holidaying in the US.
Consumer savings site moneysavingexpert.com has become a hub for disgruntled iPhone users and the swell of criticism has lead to many provider refunding those who had been hit with the biggest bills.
Martin Lewis, the public face of the site, told the Telegraph: "Those who have paid when they shouldn't have, should contact their network immediately and demand a refund.
"In some cases, we're hearing the networks are paying out without too much argument, which could indicate this is a known problem. Let's hope it does not get brushed under the carpet."