With many consumers left confused by supermarkets making unacceptable changes to their online orders, UK consumer advisory board Which? and the EU Commission offer some practical guidelines to your rights when purchasing via the web.

Numerous supermarket chains offer an online shopping and delivery service providing a simple and convenient way for elderly, infirm, isolated or simply busy people to purchase and receive groceries without needing to visit the physical store.

However a report released September 30 by UK-based independent consumer watchdog Which? has found that one in five online shoppers at British supermarkets Tesco and Sainsbury's has received poor service.

The affected consumers complained that they had received unacceptable substitutions - unavailable products being replaced with a supposed alternative. According to Which?, one consumer received a chocolate pudding instead of the black pudding [a type of sausage] they ordered and another shopper received a lemon bathroom cleaner instead of fresh lemons.

In these situations Which? advises that consumers have the right to return a substitution they consider unacceptable at no cost. The rights of consumers shopping online are also outlined on the website of the European Commission.

EU regulations state that all online sellers are required to provide the following: a postal and email address, the main characteristics of the goods, total price including taxes, delivery costs, payment arrangements, the validity period of the price; consumers are also advised to carefully check the terms and conditions stated on the retailer's website.  It should also be noted that the EU Consumer right to cancel any purchase within seven working days does not apply to groceries.  

More information about consumer rights in the EU can be found at: http://ec.europa.eu/youreurope/citizens/shopping/online-shopping/index_en.htm

More information about Which? Can be found at: www.which.co.uk