If you wish to return a faulty item bought online, you shouldn't incur the cost of returning it.

If the retailer is insisting you pay, use this letter to challenge them.

[Your address and contact number]

[Company/supplier's address]

[Date]

 

Dear Sir/Madam,

Reference: [order number]

On [date], I placed an order for a [item] and it was delivered by you on [date].

I have discovered that the [item] has the following problem: [give details].

The Consumer Rights Act 2015 makes it an implied term of the contract that goods be as described, of satisfactory quality and fit for purpose. 

Any returns policy that says I have to cover the cost of returning items must only relate to the situation where I change my mind about the item ordered and not where there is a problem with the item. 

I should not lose out financially as a result of your breach of contract and accordingly all costs of returning the item should be met by you. 

I also require you to confirm whether you will arrange for [the item] to be collected or will reimburse me for the cost of returning it.

I look forward to hearing from you.

Yours faithfully,

[Your name]

https://www.which.co.uk/consumer-rights/letter/letter-to-refuse-paying-the-cost-of-returning-a-faulty-item