i been charge for redownload the apps that i already buy before? how to get apple attention since my complaint to the publisher seems to be ignored

recently i have found some of my apps publisher have charge me for the second time i redownload the apps. i already purchase the apps before and i restore my ipad recently. after redownload the apps and try to restore the full version they did ask for my id and password (other apps did the same). however, after checking my itunes account, i find that they charge me as i just bought the app. for now i only found 2 apps that charge me for the second time:

1. manga rock

2. planning pro

pls someone guide me as they didnt reply to my complaint