Some of it could be the result of the informality associated with e-mail and texting.

Her behavior is quite common and shows a complete lack of manners. A few years before I married DH, I gave SD a cash gift for her graduation. She never sent me a thank you card or note or anything. I got on DH about it and you should do the same so he can remind her of her lack of manners.

I can understand not saying hello, but thank you is indeed appropriate and should be expected. It's time for you to speak up or she'll continue to treat you like the maid. And eventually you'll start to resent her because of it.

Good luck.

Don't offer to help her out anymore! She is using you, being ungrateful and disrespectful so don't make any offers anymore! You are not her maid or shopping service and it was very nice of you to offer to help her out at all. She sounds really rude and obviously if she's as old as she is and still like that, there's not much you can do and your H probably won't get it or see how rude it is. Parents that have bad patterns with their kids usually fail to see the problem because they don't have enough distance or perspective.

For example, I think our BM knows she is a bad mother, but literally doesn't know exactly how or why she's going wrong. She was so neglected and abused that she seems like the mother of the year in comparison to her mother, so she doesn't have the perspective that most people do of her parenting. My mom made her mistakes, like all parents, but was an amazing disciplinarian in general and gave us so much love, support and attention that she was able to raise four daughters that genuinely care about other people and do their best to be polite. My childhood and background, combined with H's wonderful background and family have helped us to be way better parents to the skids than BM. Basically, it's because we know HOW to parent and also care enough to constantly work on it and evaluate how we're doing. My skids are still young and so I expect them to continue to improve and if I don't send off two polite and thoughtful young guys to college, I will have failed as a SM. But, I can't imagine having a teenager be this rude! Obviously parenting issues have happened in the past and she is already a young woman that is rude and has bad manners. Not your problem or responsibility. Your only job here is to set boundaries to protect yourself and ensure that no one is rude to you or disrespectful. Refuse to do any favors unless you are treated with genuine gratitude and appreciation and the appropriate manners that are supposed to go with favors. Don't offer anything else! She is a grown up brat and no one should be disrespected like that.