How to delete my payment method on my apple ID?

Normally, apple says you have the "no payment" option when you go modify your payment method but it isn't popping up for me. I can only change the credit card type. It was declined a while ago because I went overboard and now it demands a new payment method before allowing me to update any current app I have or download any others (all free). How can I get rid of this problem? (without throwing my iPhone out the window)

What is the speed of slow mo video vs Real time on an IPhone 5s?

I filmed a physics experiment in slow motion so that I could get an accurate measurement of time, but I'm not sure how to convert the time taken in Slow motion to real time. For example, if something takes 4s to fall when recorded in slow motion, what should I divide/multiply that by to get the value in real time?

Not receiving text messages?

I have an iPhone and I'm unable to receive text messages, but just from one person. I'm able to get their messages, but they're not able to get mine.