that are missing from the equation. 1. How much were the planning to charge for tuning the aem in the first place. 2. Did he have a deposit down reserving the dyno ? its possible the dyno shop was counting on a certain amount of income and had to forgo other dynoes in order to accomodate this person.
There are many sides to a story. i will say that charging money to remove a car from the dyno is silly but maybe they blocked hours of time on the dyno trying to get this car sorted all the while loosing income. Who knows.... All this should be sorted out in advance imo :)