How do I get my money back from my ex partner

Try small claims court (assuming the amount she owes you isn't too large) .

Very vague question. Contractual money? Rent? Car loan? Perhaps we could help more if we knew the circumstances .

More info needed.

Did you loan her money? Did you give her money? Did you buy something for her and now that she's no longer your girlfriend you want it back, or want back the money you spent on it?

The problem with "loans" when you're in a relationship, is that they often aren't considered loans until you break up. So, if you gave her a loan, did you have a written contract for her to pay you back? Did you have a time frame for when she had to pay back? Did she make any payments towards this loan? When was the loan given? How much was the loan, how much, if anything, did she pay back?

You see where I'm going? You can't make a gift into a loan just because you two are no longer together. If it was a loan, you should have treated it like a loan from the beginning. A written contract with her signature, a time frame for paying it back. Interest. Monthly payments. Did you do any of that, or did this money only become a loan after you two broke up?