Sim card recognized but somehow not? Helpeee😭💔?

So I got a mobile phone HUAWEI P9 from a friend two weeks ago and the SIM card is somehow recognized but somehow not so there's only emergency calls and if someone calls me then it says: This number is not assigned please contact the information and WhatsApp is also net give my number 100% correct and don't get any SMS or calls, I've also deleted WhatsApp 1000 times and reinstalled it and I can't call anyone myself and there's only emergency calls but the SIM card is in the cell phone because in the settings there's also my correct number and I also have my contacts & photos I understand the net 😭 I want WhatsApp what should I do please help me.

And sometimes it says that on WhatsApp

What does that mean 😭😭

Contact your provider once.

Oki but I'm 12 and don't know what my provider is, so Internet provider Telekom but otherwise I unfortunately know it is net and my father also tried to help me but it was net

Your parents must know? You also signed a contract

So cell phone contract ne have a friend's cell phone but I haven't topped up the SIM card for 2 years or more but I can ask my parents again but I'm terrified that I will need a new SIM card because that's awesome expensive😭😭

Your SIM card (and the phone number that belongs to the card) is no longer alive. So you have to buy a new one. And it's not expensive.

Why is she no longer alive 😭 and how much does a Sim card cost