My friends!?

Ive moved away from the town where i went to high school and i have always really tried to keep in contact with my friends, but im starting to feel like its really one sided, they hardly ever call or tex and by hardly i mean like every 3 months i hear from them. I always send chrissy cards and always send a birhtday present or a card i have never gotten anything in return, even on my 21st, i went to all of there paties and wot not. How do i bring it up to them in conversation how i feel? Or should i start treating them how they treat me?