Update and download problem

Recently I am unable to download any new apps, previously downloaded apps, update existing apps and can no longer do any in app purchases. It all started last week, I was doing several in app purchases until it stopped working as it should, I get no notification to confirm purchase, my app freezes, when trying to download or update apps, it has a loading symbol where the “get” or “update” button is, it just keeps buffering and nothing happens. I don’t get any error message until after I had switched my phone back on which says “unable to purchase”. I’ve contacted Apple support over a dozen times, but I get no straight answer and I get fobbed off to different advisors. Can anyone help!?!? I can’t download anything new or update on my phone anymore.