No - you're not being unrealistic. I had a SIL that did the same thing....only on one occasion she called me, laughing, and told me a "story"....well, the story ended up them laughing and joking about what I'd MADE her!!!!! That was the last present I ever gave her. I made her brother buy her presents from then on...and if he didn't buy her one, so be it! Give them another week and call to say you wanted to double check if the items got there. If they say yes, then remind them that it would have been nice for them to have acknowledged it.