Increasing speed of worksman trike

I recently bought a 2021 worksman etrike. It wasn't running when I bought it but I've since been able to get it going. It uses throttle only and doesn't have pedal assist. My issue is it only does 6mph! I'd like to have it do 15 or 20. It has a worksman/bafang 850 watt front hub, the apt/bafang 850c display and a 48v system.  I can't identify if worksman built the speed controller or just put their name on it. I have tried to adjust the speed in the display advanced settings and it makes no difference what I do. Is there any way to get this trike going faster? It's unsafe to ride in my area at such slow speeds. If anyone can help me I'd really appreciate it!