Respected Sir/ Madam,
My name is __________ (name) and I am writing this email to inform you that I am using __________ (mention name of the service) and for which monthly payment is being debited from my _______ (mention account) and this is to request you to kindly change the account number to ___________ (mention account) as ___________ (mention reason).
In this regard, for any query, please contact me at _______ (mention contact number).
[Digital Signature – if applicable]
____________ (Contact details)