Brits are having to pay over the odds for costly premium rate tech support lines, according to Which? Computing.
"Some companies are using higher-cost numbers at their customers' expense. If other companies can offer a freephone number, why can't they all?," said Sarah Kidner, editor of Which? Computing.
All of the companies that used premium rate numbers said the revenue generated "covered the costs of a technical support service".
A spokeswoman for Tesco said: "The cost of calls to Tesco broadband technical support is something we've been looking at and listening to customer feedback on".
Which? also said the average waiting time on a technical helpline call was one minute and 33 seconds. PlusNet was revealed as the longest wait, with customers claiming they had to endure an eight minute wait on average.
See also: Free open source helpline opens