One time charge

A one-time charge of $25 was added to my bill this month.I believe this is due to the fact that last month's direct debit did not successfully debit my account and I was unable to make the payment (I immediately paid it with my debit card afterwards).

I am not sure why the direct paying from the chcking account failedlast month, but I am not convinced that the one-time charge was incurred because there is no defect on my part.

Thank you