Parental Controls

Hello, I'm doing my A/Ls, I have a little old iPhone 5C until my exam and I have Telegram on it.I blocked access to adult content in Websites and Browsing via Restrictions.But when i use Telegram I usually get those adult sites and explicit content when i use it for study purposes.I don't have any control methods up to now to restrict myself from seeing them.From everything i tried my best, but couldn't.Because though i restrict in WiFi router as those contents are withing telegram app it won't restrict, and also from the phone system, there is no control.Please help me to Focus on my studies