[Your address and contact number]
[Warranty provider's address]
Dear [Name of person you spoke with on the telephone],
[Reference: warranty number]
I write further to my telephone call on [dd/mm/yy].
On [dd/mm/yy], my item developed the following issue: [details of the problem experienced].
I contacted you and asked you to make arrangements for the item to be repaired, however you have refused on the basis that [set out the reasons the warranty provider has given].
The warranty is a contract between me and [name of warranty provider].
Although [specify the issue] is covered by the warranty, you have failed to agree to the repairs being carried out and are therefore in breach of contract.
[Set out why you do not accept any reasons the warranty provider may have given for refusing to carry out the repair]
I would make one final request for you to carry out the repairs in accordance with our contract.
If, however, you are not prepared to do this, I will have no choice but to instruct a third party quote for carrying out the work.
I will then forward you a copy of the quote and seek reimbursement from you in full for the cost of repairs along with any other associated losses I incur, if you continue to refuse to carry out the work.
I look forward to hearing from you in [give a reasonable timeframe depending on the urgency of the repair].