Plants do get mixed up sometimes in a busy potting up area. Could just be the clump forming type. If you have a label and keep till tickets. Take a photo and say it does not do what the label says. Under Sale of Goods act....money back or correct item.

Too true Dorjac I bought trays of double Petunias this year and they were singles. They admitted that all there singles had been wrongly labelled on one delivery. They gave me a choice of refund or replacements I took the refund and have lots of singles as it was too late to start again.