+100

I think Sammyg2 got it right. Tell them you don't want their money and would rather your friend keep his friendship with them and use the backdoor and wipe it all out. Give them a couple of leads on someone who will do the work. Do it nice and about a week later they will be glad to pay your agreed upon price.

I've thought about adding a clause in my I.T. 'contracts' that state a portion of the client's I.T. network can/will be disabled for non-payment.

I wouldn't do it unless the situation was really really bad. In a situation like this though I'd consider it. Probably something as simple as disabling Internet and VPN access. Perhaps even limiting server access.

A difference though is my customers must agree to all my terms ahead of time. Everything is spelled out on my website. After they agree then the work begins.

Highly disagree with the bolded part.

In IT, your reputation is EVERYTHING, and even a whiff of behaviour like that, regardless of "justification", can ruin you.

Others won't care, or hear about, WHY you did it, just that it was done, and that can kill you in the long run.


$0.02

Use the backdoor?

Dude, that sick! Not that there is anything wrong with that...

It would simply be unethical to 'use the backdoor' and remove all of my work.

Everything I do, I do with permission of the business - as a professional you have to make those decisions based on that assumption. They have not given me permission to disable their business.

I know it seems wonky to say the least but it is unethical - just as much as it is unethical for them to stiff me of course. Two wrongs do not make a right.