Name changed as outing and posting for traffic.
Late last year it was my stepdaughters 16th birthday. Her main present from DH and I was a Tiffany necklace - the standard dog tag pendant one - she loved it and wore it every day until around Christmas. Since then she's not worn it - no big deal at all, however, tonight over dinner she said her mum has taken the necklace and wears it everyday, has done since the start of the year. She said she has asked for it back several times but said her mum made a joke saying now you know how frustrating it is when you use my makeup and trainers. She says she sleeps with it on so can't just take it back and has given up.
I feel sad about it to be honest. What do you think can be done about this? It's not right to have her special birthday present taken away from her like this.