If you would like to confirm that you have received full payment, here is a sample template you can use to write a letter acknowledging payment in full.
To [Recipient name]
Dear, [Recipient name]
This letter is to acknowledge the full payment of [Amount] that was received on [Date]. The amount was deposited to my bank account number [Number] from your bank account at [Name of bank]. The identified transaction number is [Number] and was made out to [Name of company].
With this, we would like to inform you that your outstanding dues with us are paid. We appreciate your promptness regarding all your payments. We would also like to thank you for your business and look forward to doing business with you in the future.
Thanking you again.
[Name of company]