Uh oh. Sounds like a mix-up to me. If you paid for a pure bred you may want to contact the breeders and tell them about this. With stuck-up ears you cannot show her, and should not use her for breeding "Maltese". Hopefully they will offer you a part refund, but if they get funny about it, I would contact the Kennel Club your pup is registered with, and tell them that you suspect she is cross-bred, as obviously this affects anyone who bought a pup from that litter.
They may suggest DNA testing the lot of them to prove/disprove the breeding.
They may suggest DNA testing the lot of them to prove/disprove the breeding.