When you say they had to make it is this a made to measure kilt or did you have to wait until they did a run for them to have an off-the-rack kilt in your size? If it is a made to measure kilt, your chance of having them remake or fix it for free are nil since I assume you do the measuring.

You cannot compare sizes of kilts between makers. While they may use the same measurements they may not represent the same thing; you need to ask each time you buy from a new maker.