I want to send a letter to one customer telling that I will charge one month rent as a penality of returning the vehicle earliear than the date mentioned in the rental contract. please see below and correct it.
This is regarding the lease agreement for the vehicle you hired from us.
Please be informed that a one month rental charge will be charged to you as an early termination of your lease agreement as you have returned the vehicle earlier than the agreed return date.
Please acknowledge this letter and send your confirmation.
I'm pretty sure it's all technically correct?
I would change "regarding" to "in regards to" just to sound more professional. And "as an early termination" to "for an early termination".