To everyone who has a problem with an increasing collection of temporary files, which grows to a very large size and cannot be deleted using normal methods. I had this problem on my (3) (after a few months, the file collection was almost 400GB!) and technical support gave me the following solution, which worked:
in the phone app, type exactly what follows the colon: *#*#569#*#* and after the asterisk, the log control tool should start. Go through all the items and, if necessary, disable the options that save logs. Then go to the three dots in the upper right corner, to “Log list” and there again to the three dots, click Deep clean log, Dump data usage and finally on the trash can. This should work.
