don't like to add fuel to the fire, but did she sell the others at a more expensive price than she paid you? You should buy some customised labels if you don't have a proper stamp yet. If anyone tries to take mine off they would rip the card.
I'm glad for your sake that she said it in front of the other dart players too, it might make her realise just how underhanded she is being. xx
and just in case
www.ablelabels.co.uk is where I buy mine from, they're not expensive plus you can have ALL your details printed on them plus a little image. I have
my name , tel, email, and a little black duck on mine. HTH Jacqui xx