So sorry to hear you've had all these hassles - your poor kitten too, it's such a shame people don't care for their animals properly and are so unscrupulous!

As for the sexing, I suppose mistakes can be made. When we got our kitten we were told it was a female and had been flead, yet when I took it for a check-up and jabs a few days later at the vets I was told it's actually a male and had flea dirt on him so had to pay for a further flea treatment! I couldn't really complain though as we got him from a friend and didn't pay anything - a breeder should really know better!