Hello, this is Jim and I’m a dual-qualified lawyer (UK & Republic of Ireland) happy to help you today.
You are covered under the Consumer Rights Act 2015 here which means you have a right to expect a service (from the insurer) carried out with reasonable care and skill. They also need to be transparent with their fees and charges - if not then the court will void those extra charges due to the fact they are weighted in the mortgage company's favour and not yours. They would be considered unfair contractual terms.
You should complaint by email to: [email protected]
This is the email address which the Financial Conduct Authority have for them (https://register.fca.org.uk/ShPo_FirmDetailsPage?id=001b000000MfSraAAF). If you want to double check the email address with the FCA then please ring them on 0800 111 6768. You should see from the above link that the complaints email is the same as the one above though.
You should now make a formal complaint and if that does not resolve the matter ask them for a "deadlock letter", which is a letter giving their final response.
Once you have the deadlock letter the next step would be to escalate this to the Ombudsman - they will investigate and liaise with the company which would hopefully result in a write off of the excess charges. They can order the company to make a financial award for inconvenience if they have acted badly (which they have in my view).
You can make the complaint here : www.financial-ombudsman.org.uk/consumers/how-to-complain
Based on the circumstances, assuming the mortgage company does not uphold your complaint, I am sure the Ombudsman will do.
I hope this helps? If you would kindly leave me a 5 star rating (at the top of your screen), the question will stay open and any follow up questions are welcomed.