Your cache was probably flagged. They flag caches when an account is temp banned, any other accounts that have used the same cache are automatically flagged.
I've had the same thing happen to me on brand new accounts, and I've been able to bypass it. One account is temp banned, all others that use the same cache after the temp ban, appear to be flagged for deeper investigation and are permed within 24 hours.
One solution is to login each account one at a time, if you're temped, immediately delete any and all Jagex related files. I keep two accounts max per cache, using this trick
https://villavu.com/forum/showthread.php?t=109112 One if you want to be careful. Another is making it so the client instances the cache, but that's only really viable for OSRS since the cache is so small it takes <10 seconds to re-download.
- .jagex_cache_32
- jagex_cl_runescape_LIVE.dat
- jagexappletviewer.preferences
- random.dat
Are all the files I delete from %userprofile% (C:/Users/USER) after a temp ban. I have a directory with a completely untouched cache and client settings, so I just delete everything and copy over the untouched cache. I also set random.dat to Read Only.