Useless subtitles on TV, no mirroring from the Phone.

I have an 8 or 9 year old LG smart TV. The subtitles on Showmax does not sync properly and only shows around 30% of the time. Being hearing impaired, this means I cannot watch anything. On the phone app however, the subtitles work just fine. Problem is they won't allow you to mirror the phone to the TV! Completely useless. Netflix works fine.