Manipulative colleague

Could you please advise me on how to handle this situation, as I’m dealing with a toxic and manipulative colleague?

We didn’t use to communicate much, but over time they attached themselves to me — inviting me to lunch, asking about my personal life. Shortly after we “became friends,” they borrowed 10 euros. After that, the amounts kept increasing. For the second month in a row now, they have been asking for help and to borrow significantly larger sums. They do repay the money, but I think it’s only so that I’ll lend to them again.

I feel like they see me as a “piggy bank,” taking advantage of my kindness and pretending to be friendly. What’s strange is that they seem to live comfortably and can afford quite a lot. If they’re short on money, they could borrow from their own circle or other friends — but they specifically latched onto me.

When we order lunch together, they don’t contribute to delivery fees either. I’ve never received anything from them in return, even though I often had to treat them to coffee that we buy together with another colleague. All of this feels like a pattern of behavior.

What should I do? I’m tired of feeling foolish. How can I deal with this situation?