QTX QX12PA Speaker Display Not Working

I have a QTX QX12PA PA Speaker where the digital display screen is no longer lighting up and the USB/SD/FM inputs are not functioning. However, I can turn on the bluetooth and connect no problem and sound output from this connection works fine along with the volume and level controls. They feel like 2 separate systems when operating them on the back of the speaker so I'm guessing something has gone wrong with one of them. Any ideas on where to start?