Homebase and B&Q rated worst online retailers
Homebase achieved a customer score of 57%, with shoppers giving it two stars for the range of products and two stars for value for money.
Customers complained about the retailer ignoring complaints and selling products that were actually out of stock.
DIY.com (B&Q) scored 59% with shoppers complaining about the difficult-to-use website.
More than 7,500 were polled by Which? for the study where they were asked to rate their experience in buying particular items, value for money, product range, ease of ordering, deliveries and product quality.
The top of the table is lined with specialist retailers. LizEarle.com, RicherSounds.com and WexPhotoVideo.com all scored 93%.
Customers told Which? that these shops offered top service, great value for money and an extensive range of items.
Harry Rose, editor of Which? magazine, said: “We continue to see the same brands performing poorly in our survey, with some of the bigger retailers offering disappointing levels of service and inferior websites which often seem to run out of stock.
“Our research shows that if you value a genuinely enjoyable shopping experience, then you might be better off with a smaller brand that can offer a more personalised service.”