Many internet firms in Europe are not treating customers fairly, according to a report from EU consumer bodies including the UK's Citizens Advice.
Complaints against online retailers are on the rise
Late or non-delivery of items and defective goods were the most common complaints against internet traders.
Europe-wide consumer group European Consumer Centres (ECC) received 3,775 complaints about internet sales in 2005, a 74% rise on the previous year.
One of the biggest problems was the poor handling of complaints.
The report said that when customers had a problem with a delivery or a defective item bought online they often found it hard to contact the seller and get redress.
Problems were most acute when consumers bought items from internet auction sites or from retailers based abroad.
The ECC was set up to resolve problems related to goods and services bought cross-border. Citizens Advice operates the UK office of the ECC.
Ruth Bamford, the Citizens Advice ECC director, called for tougher consumer laws to enable consumers to obtain redress.