28/5000 Problem with survival worlds

I had a non-premium version of minecraft and everything was fine, then I decided to buy the premium and now the survival worlds that I do get corrupted, I go to a remote area and the chunks get corrupted, and when I try to get out it locks on the screen saving, and having also cease when I remove it open it locks, and also when I enter the end or nether and it happens to me with all the mute ones that I do and with those that I had to those that I gave them a lot of time