I would think that they have to honor the pricing you were given a receipt for. I consider that when someone takes possession of materials it is considered delivered. Not my problem if they get back logged, items get lost etc. As long as you have that dated receipt ANY business that wants to keep its good name and rep has to do what is right and honor what was quoted. I will tell you this, if they don't I would be looking for someone else to do business with. Good luck keep us informed.