[opless]

Absolutely.

FU Pay me.

A polite email to the Finance director, or CEO ought to do the trick, and wait a week or two, warning them about the consequences of non-payment and interest on the debt.

Then after the time limit has passed pop down to your local court house to file a small claim or a winding up order if your client is local. You could also sell the debt to a third party. Then it's their problem.

[ocodo]

> warning them about the consequences of non-payment and interest on the debt.

You cannot simply add in these penalties though, not suggesting you are implying that.

However any such clauses / penalties need to be clearly laid out in the initial contract, and the contract also needs to be legally enforceable. Always check with the relevant jurisdiction what acceptable penalties are, and get a lawyer.

[opless]

It depends where you are. In the UK you can add interest to outstanding debt.