HELP! User submission was working fine now part has stopped working

HI all, not sure if I need a mod or any guidance! I have a user submission which has 5 image upload buttons which worked fine in preview and live, the user submission then loads to repeaters on the website, I upgraded to premium 8 days ago and all has been ok. Checked Monday and still ok, checked yesterday and image 1 of 5 is showing upload error with no file to upload reported in console log, if you upload image 1 again it does it but when you submit the entry is duplicated. I haven’t changed any code, just all of a sudden stopped working!