Internal storage fills up I had a sony xperia C with a 16GB memory card... My internal storage kept filling up which made it unable to update or download any apps. The only apps i had was whatsapp and instagram. Sent my phone in. Had to pay for repairs, was in for 6weeks and got phone bback but still same errors... I got a new phone (Huawei G6), brand new 16GB and a new google play store account... phone set to default storge location is SD card.. moved all app that i could to sd card. I only have 10 songs and about 100 pictures... I clear cache everyday probably 500 everyday. I really don't know what I'm doing wrong please help.
It seems your internal app partition is full. Check it on Settings> Storage> under phone storage what left as available on app section. If it is full (150mb free is not usable) you have 2 options: 


You can swap your external SD. You can read full note here: (NB: it works if you have a MTK device, I don't know what if other devices) How to swap phone storage with SD card
Partition of external SD. read it here: How to Partition SD Card and Use Link2SD in any Android Phone with Screenshots


Hope it helps.