Problems with 4s and IOS 8.4

I have an Iphone 4s and recently tried to update to the 8.4 firmware. Initially when I tried to update it seemed as though the update had completed. Three days later half of my applications stopped working (Apple store, Safari, Instagram, youtube ect) and advising there was 'no internet connection' however the working apps (such as Facebook, chrome) were still using internet. I connected my phone to Itunes and realised the phone never actually updated to 8.4. Thinking it may be having the issues because it did not fully update, I backed up my phone and updated again. The problems were still occurring. I then restored the phone to factory settings and the problem still exists! Most applications are advising no internet connected however other apps are still using internet. Some blogs advise to simply re-download the apps however I cant as I can't access the apple store! I am currently traveling for an extended period of time, currently in Croatia so going into the Apple Store is not an option.

Please help!

Thank you!