Once you have decided to buy something over the internet, be sure you know what is being sold, the total price, the delivery date, the return and cancellation policy, and the terms of any guarantee.

Other points to remember are:

• save all information relating to the transaction

• take care with the information you give out

• check the privacy statements

• check the security of payment details

• you may have some extra protection if paying by credit card.

Saving information

Save all information possible relating to your order. This might be pages from the supplier's website (eg the advertisement), the completed order form, and any e-mails.

Suppliers in EU countries should provide you with key pieces of information before your order is finalised. For example, they have to give you the identity of the supplier, the main features of the goods or services, the price, the arrangements for payment and any rights you have to back out. All of this must be given in a clear and understandable way.

The supplier also has to send you confirmation of the order.

Take care with the information you give out

Be wary of giving out your bank account numbers, credit card numbers or other personal information to a company you don't know or haven't checked out. And don't provide information that isn't necessary to make a purchase.

Privacy statement

Good companies are likely to have privacy statements on their websites. In these they will explain what they do with the information they have about you and how secure the information is.

Such companies will also allow you to say whether or not you want your information passed on to other companies.

Any company that sells or passes on details about you without your consent could be breaking UK and European law. Outside the EU there may be little action you can take against, say, a US-based company that has information about you.

Paying by credit card

You may have some extra protection if you pay by credit card. If you have a claim against the seller for breach of contract or misrepresentation - for example, if goods were not supplied, or were faulty - you may also have a claim against your credit card issuer. This could also be useful if the seller goes out of business.

This applies to goods or services costing more than £100 for one item (but less than £30,000), even if you have only used your card to pay a deposit.

Remember, you do not have the same protection if you pay by a debit or charge card.

Further advice can be obtained from your local trading standards department or Citizen's Advice Bureau.

Security of payment details

Many companies allow you to send your credit card details via a secure (encrypted) page and you should aim to buy from companies that give you this choice.

You will be able to see on the screen whether the page you are on is secure. Often it will flash up a warning as you enter a secure page and you might see a closed-padlock symbol in the status bar at the bottom of your screen. If a padlock is not there, and there are no other guarantees, you should think twice about buying.

Fraudulent use of your payment card

If someone uses your payment card (including debit, credit, charge or store cards) fraudulently to shop on the internet without your permission, you can cancel the payment and your card issuer must arrange for your account to be re-credited in full.

How to complain

Contact the trader with details of your complaint, and give them a chance to put the matter right. Put your complaint in writing and make sure you include this information:

• date of advert and website where it appeared;

• date of your order;

• details of goods or service ordered;

• amount paid and the method of payment;

• any reference e.g. order or customer reference number;

• the reason for your complaint;

• anything else you think is relevant;

• how you would like your claim resolved.

Keep copies of letters along with a diary of events and a note of any telephone calls.

Consider withholding any further money until the problem has been sorted out, but check the small print of any contract you have signed. You should be especially careful about withholding payments if you have taken out a credit agreement