Downgrading/installing an older version of PHP

Hey.

So I was trying to downgrade php version from 7.0.11 to 5.x (preferably 5.6) and, long story short, I failed. Then I tried to remove the 7 and install 5.6 from the zipped archive. Downgrading with a guide didn't work out, because I didn't manage to make ppa work on kali, unfortunately. Removing php7 and then installing it from the archive caused a huge mess with dependencies, and overall, my whole system is a mess (yeah, I'm bad at this). Could anyone guide me through on how to have php5.6 on the newest distribution(rolling 2016.2)?
Some info on how to remove/purge the 7 completely, including all config, cache and other files that could be located across the drive would be helpful aswell.

Thanks in advance.
Vane