Is this a mean or bad decision to make?

My brother's ex (30 yrs old) always aked me for money because she's not working and because she has two children with two different men and one is not paying child support. Anyway she managed to get a job, but continued to ask me for large sums of money-$1,000, $500,$3200, anyway I said no to the $3200 because I'm a student my husband is an engineer and like it's getting ridiculous having to run around to send her money through western union. So I said no and she's been rude to me ever since. Then she quit her job-because she said it was boring...so she began asking us again. Then yesterday I tried to send money through Western Union, but something happened with their computer and the money got sent somewhere else and they said it might be cleared up today and she'll receive it today, but she "needed" it yesterday to check into a hotel with her and the children because she's moving. Anyway the point is I felt really bad, but at the same time it wasn't my fault and I feel like I was responsible for not getting her a hotel. I've decided to no longer put myself or for that matter ourselves in these positions anymore to be held responsible for the fact that a 30 year old who is capable or waitressing, working at McDonald's or whatever refuses to get a job and instead just leaches off me and then is mean to me when I say no. Am I right to feel this way or am I over-reacting? Also I found out that when she'd ask for money to pay a bill or something- she'd end up getting her hair done and even got a tattoo and my brother has been paying her rent and taking care of her so it's like she just asks me for money to shop and do other things and buy Xanax-she's addicted.ugh I know it's my fault for being so naive, but now am I being too mean?