Write a letter to your insurance company to complain against fees increase

Dear Sir /Madam,

I am writing to you as I have recently received a letter from you informing me that my monthly insurance fee for my car is going to be increased by 20 % (as) from next month. As from> formal writing

I do not see any good reason for this increase. It should in fact at least have continue to decrease over the years. I am a client of your company for over 10 years, with several insurance contracts. Moreover/Besides that,, I neither have neither (ever) been involved in any car accidents, nor have I ever requested any assistance from your services.

Given all the above reasons, I would like to remain/stay a satisfied customer, however I would (really) appreciate a discount, or at least an assurance that my fees will be the same for the next 2 years/ a promise to keep my fees at the same level for the next 2 years.
Furthermore, many other insurance companies have offered me/are offering me much better rates/really interesting rates for all my insurance needs, with the same terms and (level of) service.

I look forward to hearing from you