Cellular Internet Problem

Hello,

I recently transferred my number to a new carrier. After the transfer i inserted my new SIM card to my iphone and started using it. But apps which normally require internet to work properly OR send notifications do not work correctly UNLESS i open them manually. As soon as i connect to a WiFi i get a lot of notifications at once and these notifications are dated back to like an hour ago or 3 hours ago which means i should've got them earlier. My guess is that apps cannot connect to internet when runing on the background or not started at all. When i manually start them they do get connect to internet, i can connect to internet over Safari. The problem is that i'm not getting notifications for my news apps, WhatsApp, Instagram etc. Here's what i've done so far:

- Updated my carrier settings at settings-general-about

- Checked if cellular network is enabled, notifications are on

- Restarted my iphone several times

- Backed up my data and resetted iphone back to factory settings

- Manually AND automatically updated cellular network options(APN etc.) for my new carrier

To summarize; apps (including Safari) can access to internet over cellular data IF i start them manually but i'm not receiving any notifications (WhatsApp, Instagram, news apps etc.) from them. This started when i started to use a new carrier and a new SIM card.