[Your address and contact number]
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.