cannot download item bought on iphone to ipad

hello, i bought atari greatest hits on my iphone and downloaded a couple of game four packs that also are supposed to work on ipad. but they wont download to ipad. first it wouldnt "restore" i think becuz the cell service is lousy where i was, then tried on wifi at work but says still cant and even on a better cell phone place it still wont. i get error message of " incorrect data size. internet connection might be blocking download. try another internet connectiom." the other thing was it didnt want to restore so i just clicked buy on my ipad figuring it would realize it had been bought and say so. can anyone help? games are great but iphone 6 screen too small so would like games on ipad which theyre supposed to be compatible with.