Several months back I had setup the accounting software for a new shop and integrated with their till system. There were other accounting related tasks.
I have worked with them in the past and had a very good relationship with them. I have done premlinary work with them as well without charge. I did't know how long the work would take hence charged an hourly rate.
I billed them on a monthly basis and since there were a new business I had give them time to pay. Suddenly they went to a new accountant without informing me. After sending the invoices to them several times they are questioning the charge saying the new accountants would have charged a lot less for the work and onlly accepted the hourly rate as they didn't have a benchmark against. Invoices are around 6 months overdue.
I have tried to be fair and not bill all my time as they were regularly sending messages etc since they do not understand anything about accounting/tax. The engagement letter and detailed invoice has been quite clear about the charging on an hourly rate.
This is the first client that has ever questioned my fees and have a dilemna reduce the fees and take the hit which would be annoying so I have gone out of my way to help them or possibly takem the to court which is just hassle and time consuming with having to gather all the evidence.