How to join Wi-Fi automatically?

My Wi-Fi at school is annoying… Every time I close my device, it disconnects. Then when I want to use the Wi-Fi, I have to go into settings>Wi-Fi, then it brings up the page and you have to agree to the terms and conditions. Every time. I'm on an iPhone 7 btw. Is there a way to bypass this terms and conditions page so my phone stays connected?

What should I do about my phone contract?

My phone contract for my Samsung Galaxy S6 ends in late September next month. Iceberg been using this phone for the past 2 years. My dad says that I should stick with the same phone but get a sim only deal with plenty of mobile data. The thing is, I would but the S6 has such a terrible battery life even if I use it in power saving mode. I was thinking of getting one of the 3 new iPhones coming later this year. But that would be way too much money, so I'm thinking maybe I could find a good deal for iPhone 7 Plus and if I can't get that maybe a OnePlus 5 and if I can't get that I'll compromise and get an iPhone 6s Plus. I use O2 (UK carrier). What do you think I should do?

Why can nobody hear me when I call them?

I had spilled a little bit of food on my iPhone 6 and it was stuck on headphone mode so I looked up how to fix it and I found where you can use a Q tip so I tried it and it fixed it but now when I call someone they can't hear me unless I have it in speaker or headphones in. Can someone please help