Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaargh!!

That just about sums up my annoyance at the high-pressure cold-calling I am suffering since buying my iPhone.

I have mentioned in previous blogs that I am somewhat of gadget geek, so when O2 recently improved the minutes package that comes with the eponymous device I took the plunge an signed up.

I may have thought twice if I had known the barrage of calls I would suffer from a telesales company flogging mobile phone insurance.

They started one day after I activated my new phone. Call number one congratulated me on my purchase and would i like to take out insurance on my expensive iPhone? I politely declined, pointing out that I had ensured it was covered under my existing home and contents policy.

But that wasn't the end of the matter. Instead of being ticked off their call list I seem to have become a challenge to them. I get at least one call a week, and with each call my tone gets less and less pleasant. They still haven't got the message.

This kind of practice is deeply unethical, but sadly practised by many telephone sales companies. If you find yourself on their calling list stand firm and insist they remove you.

Make sure when you sign any contracts for mobile phone services (or any other form of agreement on paper or online) that you tick or untick the box that refuses permission for the company you are dealing with to pass your information onto third parties. They tend to make the boxes small and hide them away as they don't wan't you to option out beacause they receive money for every name they pass onto these telesales firms.

It's also always worth checking when considering insurance for specific items whether they are covered by existing policies such as your home and contents or even as one of the benefits of your credit card if you purchased the item with one.

Even if the item isn't covered automatically it is often very inexpensive to extend the policy.

Fed up with companies trying to sell you something you don't want? Vent your rage in the Moneywise Forums.

• Mark Stammers's blog