Why is it there are no option to have on-screen navigation control?

[Windows Central Question]

I have an 830 for 1 year now. In 8 months, the loudspeaker don't function anymore and this month, the navigation keys don't work anymore. It's been 2 weeks now and I still don't find any repairman can do the work. Please help or do message microsoft about this matter. Thanks in advance!