Due to the fact that this product is made on customers demand, customers have no cancelation or refund rights by EU law. Sold B2B or B2C doesn't matter. There is just one date they have to met to stay within their contract: delivery within Q3.
If there would exist any contract i entered, there should exist a paper with some blabla and with my and ATs signature. Cant remember to have seen such a paper.
B2B or B2C usually make contracts among themselves, but i cannot perceive such act.