What to do when they pay the original invoice value but don't pay the interest & compensati?

Hi

This is always a difficult one as the compensation and interest are not usually large enough to justify extensive work in collections.

It also depends on your relationship with them and whether there is on going trade.

You are fully entitled to continue to pursue it.

You could invoice it and keep the balance on the clients account. There is no requirement to raise an invoice though as it is not a vatable supply. But most accounts packages needs you to raise an invoice in order to recognise the debt.

How much time and effort you decide to put into pursuing it will be a commercial decision. Although for many it is a matter of principle.

You could go as far as applying for it via moneyclaim. Sometimes just telling people that you will take that step next is enough to make them pay the compensation.