I've raised £960 to someone hacked my Xbox and got my mothers bank card and has spent £960 and we can’t get a refund as the fraud bought digital codes. help

I am 16 and was playing on my xbox and my mother burst in my room yelling at me showinb me her bank statement assuming i had spent almost £1000 on my xbox as over 3 days online purchases had been boight in my name but i had not purchased any of these “fifa points” i do not even have fifa i prefer rugby and of course me and my mother tried to get a refund but it was denied as it had been too long and the codes had been used and bought in my name i join the royal marines this septmber and do not have enough time to pay my mum back and i am worried for her as a grand is alot of money to us and we are appualed that somone could do that to a stranger and we are in desperate need of any money to help us get the thousand pound back. Please help me and my mother