I have 3 granddaughters who I had a very close relationship with until the youngest one was 10, and we moved 4 hours away. We still keep in regular contact via text. So when I didn't even receive so much as a birthday card from the oldest 2 who are 19 and 18 last year, I was really disappointed. I mentioned it to my daughter, and she said 'oh, you know what kids are like', and just brushed it off. I told her I felt it was her place to have reminded them that my birthday was approaching, and she said she 'hadn't thought about it'!! It still rankled somewhat, so the next time I spoke to the eldest one, I said 'Oh, thanks for the birthday card', she came back with 'oh, sorry Nana, I didn't think', so I just said well now that you have a job, and expect to be treated as an adult, it's time you learned to do jobs like this off of your own back, you need to keep a diary of some sort to remind you, and not rely on others all the time. After all, how would you feel if I forgot your birthday?' To my surprise, the lesson has been learned, I received a card and small gift in the post last week! My birthday isn't until next week, but she was going on holiday and wanted to be sure that it arrived in time, bless her!! The point of telling you this, is that perhaps their parents haven't done the best job of raising them, and if no one says anything, then they're not going to learn. So perhaps OP, you could send them a text and say something along the lines of I hope you got the baby things I sent, only I haven't received a thank you card yet! You never know, it might just be the kick in the pants they need.