Downgrade from lollipo

Hi,

Since upgrade to lollipop working with my LG as become a disaster.

Original internal storage is 8GB and I have an external card of 32GB.

Live in Nederland and server is T-Mobile, model LG G3s D722.

Where can/should I begin...since short lifetime battery to a crashing telephone...to an appearing-disappering keyboard to an extremely hot batery for no reason...a flashlight that only responds when "she's" the mood...and last but not least...AN INTERNAL MEMORY USE OF 5.16GB ONLY FOR THE SOFTWARE.

The last one is absolutely ridiculous. APPs, music, pictures and videos ARE ALL in my external card. Constantly clear up cache, not able to make ANY downloads nor upgrade of APPs. Always get the message that internal storage is low...REALLY!!! as if I hadn't noticed...

How can I downgrade to the older version?

Hope there's a way out of this cra***y software.

Thank you.