Payment via milestone

[sal]

You quoted, the customer accepted the quote, you did the job, the customer was happy with the quality. If you have this facts documented it's a no brainer - the client owes you the money and you have the law on your side.

If they pulled tulip like that once, do you really want to do business with them in the future?

[TheFaQQer]

My point was that I don't think that +/-10(ish) is taking the piss and so therefore the customer shouldn't be feeling like they've been ripped off.

It sounds like what the client really wanted was a time hire / time and materials with a cap rather than a fixed-price engagement. That's always a win for the client - if it takes longer, you take the hit because the price is capped; if you take less time you take the hit because they are paying a daily / hourly rate.

When I was working on proposals in consultancy, we were always told that that kind of contract should be avoided at all costs, unless there was a potential upside (lots of repeat business on better terms, for example).

It's an unfortunate situation for the OP - the client agreed to the contract which was arrived at with the best intentions of all parties, so they should pay what they agreed to.

[borderreiver]

You quoted, the customer accepted the quote, you did the job, the customer was happy with the quality. If you have this facts documented it's a no brainer - the client owes you the money and you have the law on your side.

+1