I do not work for or promote Zuku, I hate them, but ...
Being a customer for 6 plus years, their service has worked 85% of the time, to me that's something I can live with. Downtimes happen, things break, add Kenya Power to the mix, get my point. There's no where you'll get 100% quality service.
What doesn't work is their representatives on phone. Those buggers will LIE to you without thinking twice, and I always call them out on it when they do it to me.
They had me on hold on a call for over an hour (They do this to make you hang up or waste your airtime so you hang up if you aren't buying their cow dung)
Some other complaints I see on Twitter, Users need a bit of education and I don't know whose responsibility it is to teach.
Answer - I believe you are VERY far from your WiFi router and you need to boost your signal
Answer - Heavy downloads on your line.
Will competition improve service? No idea.