Mobile network iD Mobile has been wrongly charging customers for using their phones abroad since the introduction of free roaming calls in the EU, can reveal.

The firm, which is owned by Carphone Warehouse, has been charging a roaming fee if customers overseas in the EU call another EU country (which isn't the UK) – despite new rules coming into force earlier this summer to stop this.

Under the rules brought in on 15 June, while roaming in the EU you can call most landlines and mobiles within the EU (except premium numbers), paying just what you'd pay in the UK.

So if you're in Italy and call a number in France or Spain, the minutes will be deducted from your monthly allowance and you won't pay anything extra – as if you were in the UK calling a UK number.

iD Mobile, which reported having half a million contract customers earlier this year, has now apologised for the error and said any customers wrongly charged will be refunded.

See our Calling a foreign number in the EU from your mobile? MSE News story for more – plus the full lowdown on the new rules in 10 things you need to know about 'free' mobile roaming in the EU.

How did iD Mobile get it wrong?

The problem emerged after an iD Mobile representative posted in the MSE Forum yesterday (Tuesday 15 August): "If you travel to a country in the EU, you can text or call someone in the same country free of charge. If you call someone in another country, this is chargeable."

The same warning was posted on iD Mobile's website. Its EU roaming help and advice page stated: "You can use your minutes to call numbers in the UK or the same destination you're in. You'll be charged for calls to other non-UK destinations. These aren't included in your normal monthly allowance even when you're in the UK."

This appears to contradict the new EU rules, as set out in the European Commission's FAQs (see pt 11).

iD Mobile to refund customers after wrongly charging for EU roaming calls
iD Mobile has said it will refund customers

When we contacted iD Mobile to query whether this policy was in accordance with the new EU rules, a spokesperson told us it was changing its policy – and had already been in contact with the UK telecoms regulator prior to our query.

The spokesperson said: "We've been working closely with Ofcom to seek further clarification on the EU roaming regulation relating to the intra-EU call rates and have confirmed with them that we are making the necessary changes for our customers by the end of August. We apologise for any inconvenience caused and are automatically crediting any customers who have made intra-EU calls since 15 June."

The spokesperson refused to say how many customers had been affected, except that it was a "small" number who'd made calls between EU countries.

Despite iD Mobile telling us it's changing its policy, as of 4pm today (16 August) its website still told customers they would be charged for intra-EU calls made when roaming.

I think I've been wrongly charged – how do I get a refund?

iD Mobile says it's aiming to fix the problem by the end of August, and will automatically credit affected customers' bills.

If you've travelled abroad in the EU since 15 June, or are planning to do so, check your bills to see if you've been charged roaming fees while in the EU.

If you believe you have been wrongly charged and haven't got a refund in your next bill, contact the iD Mobile customer service team.