Some images not appearing.

ok I have two worpress installations that up until recently where working fine. one is the lates version and I havent updated the other one.
I noticed some of the images where not appearing corectly so I checked the links to the images and they where all fine. the media library was also only showing some imgages. if I refreshed my browser some of the images appeared. Also I noticed that if I tried to access the theme editor I got a a warning

“Due to WordPress vulnerabilities with the WordPress theme and plugin editors allowing hacks and deface of web sites, the WordPress theme and plugin editors have been disabled. To edit the PHP/HTML code of your theme’s or plugin’s files please use FTP or cPanel file manager or visit the client area of your hosting provider to have your IP address whitelisted

. I tried a fresh install of wordpress with no plugins via softaculus but it was the same and so I tried a manual install and it was the same.
I emailed the hosting and they whilte listed my ip from the terminal they white listed I can access the sites perfectly as they should be, but it still doesnt display correctly from any other ip!
the host insist there is no problem and it must be my end but I have tried numerous pcs macs phones and it isnt working properly. they say I am the only person having this issue and they hos 2000 other wordpress sites.
what do I do now?
I hope this makes sense Im feeling quite frustrated