Letter to request real estate tax refund

Hi,

we are first time home buyers and we weren't very clear about our escrow account. so when we received the first two real estate tax bills from our city, we paid them out of pocket, not knowing that the RE taxes were already paid from our escrow account by our mortgage company. Now that we found out, we called our city collector and they said that they're only showing one overpayment and that they will only refund us one payment. we do have proofs of both our checks were cashed by the city and the RE payments from our mortgage company. can you please help me write a letter requesting reimbursement on both payments.

Thank you in advance.

Vicki