Okay, actual useful answer.
Make sure your account is linked correctly. Do a forum search for 'linked account' 'account' 'linked'. There are SEVERAL threads explaining how to do this.
Second, put in a trouble ticket, Trion is great with trouble tickets. Forums aren't really the place to resolve monetary exchange issues.
https://support.trionworlds.com/
3rd: If you must use the forum for issues, try using the following template:
[XBOX MARKETPLACE ISSUE] Tried to buy bits. XBM charged, but no BITS received.
Just some friendly advice.