Play Store issue!

Just a while before receiving the 4.3 update, the Play Store had a problem, it suddenly stopped working and showed an error whenever I tired to download an app [RPC:S-5:AEC-0]. So I completely factory reset my phone and instantly got the 4.3 update. Play Store worked fine for a day before acting up again, this time it showed a 'No Connection' error. I waited for three days, but wasn't able to find a solution, so I factory reset it again. This time it refused to accept my id, luckily just a few hours later it accepted my id. Since then it been a real pain in the ass, it starts installing apps, successfully installs a few, then suddenly shows the 'no connection' message again. I read somewhere than it's a sync issue, so I synced my account, but calendar would not sync. Then I tried logging out of my account and logging back in, but surprise, now it refuses to log in to my account , and the Play Store is working just fine on my PC. Please tell me how to solve this problem!