Hi there
Goto the play store via a web browser instead of the dedicated build in app for playstore and see if you can install one. You might need to install another app called Sideloader in order to run it though.
My experience with memory boosting apps for my phone is not a plesent one. They mainly work by closing unused apps and services - however it really is a temporary solution because many services re-start back up again as they are needed.
You could just do a full reboot of the tv by holding the power button on the remote control for 5-10seconds?
Cheers
