Hi,

i can unreconcile the payment, however , the payment is still present and odoo says that there is an outstanding payment available 

i can also go to the payment and cancel it -> it will go to Draft stage

however , in my bank statement. there's still 2 operations : credit and then debit

if any accountant there can clarify... (i will ask my accountant also)

Rgds

You can simply put log note on invoice like check returned/unpaid. And ask your customer for payment/new check.