Dear Natwest - and, indeed, the rest of the banking sector,

Isn't it about time you stopped pretending that the 'chip and pin' system is impregnable? Contrary to what you would have us believe, criminals do not need to steal your card to commit ATM fraud with it.

I've had to learn this the hard way.

A few weeks back I noticed a cluster of small ATM transactions I couldn't possibly have made. I hadn't used an ATM all week; furthermore, these withdrawals included £5 notes. The machines I frequented didn't even offer that option.

I rang the Natwest fraud line and explained the situation. The revelation of the time and place of the transactions only confirmed the inevitable. When my debit card was supposedly being used in Cwmbran, it was in my possession at a Pontypool awards evening.

After a few days of 'looking into it', I received another call to inform me that chip and pin ATM fraud is impossible and that was the end of the matter. When I protested, the response was that as my partner had access to my card, he must have stolen the money from me.

Unfortunately, I can understand the reaction.

With hindsight, it's clear that I was being defrauded for months. There were a number of relatively small withdrawals I couldn't account for on my monthly statements but, knowing that my card was safe, assumed I must have made the withdrawal and forgotten to get a receipt. However there was one large transaction of around £160 I couldn't explain away - I confronted my partner about it, who denied making it. To my shame I didn't believe him, and afterwards made sure I kept my debit card on my person.

Because I was trusting enough to believe what the banks told me. So long as I kept my card safe, and shielded my PIN at the ATM machine my cash was secure. If I checked my statements carefully for mysterious payments, and didn't go around making my bank details public, I was taking the proper precautions.

If I had known about chip and pin ATM fraud - 'skimming' - I wouldn't have explained away those anomalies on my statement and saved myself in the region of £750. More if you take into account the late payment surcharges, unpaid transaction fees, and the interest on my overdraft.

I wouldn't have jeopardized my relationship by accusing my partner of stealing from me, or suffered the humiliation of having to explain to colleagues why I couldn't return their phone calls when my network access was cut off for non-payment. I wouldn't have shed so many tears, or spent so many nights awake, trying to work out why my sums didn't add up and my constant cutbacks still left me short at the end of the month.

You're not going to refund me, I know. My partner had access to my card so, by your reckoning, you are absolved of any duty to investigate the case or check CCTV. I have no choice but to accept that.

What I cannot accept is your continued insistence that chip and pin debit cards cannot be successfully cloned. There was a Cambridge research paper published on how it's done a couple of years ago, and even the Daily Mail has reported on the high number of victims.

Do the right thing.

Forewarned is forearmed.

Please spare other customers the stress and upset I've endured, and start publicising the very real risk of chip and pin cloning.