Fly.cool/Vuma unstable network

My name is Moses Phatedi I'd ***

For several times I've been writing emails and WhatsApp to Fly.cool, they work under Vumatel. Asking them to come and change my router because it's always freezing and telling me that your network is unstable. They only thing they will tell me is ' I must switch it off for sometime and switch on again and they will also say Upon checking your account, your connection is up and running and yet I not enjoying what I'm watching or doing anything,because of their network it's unstable. If there is nothing wrong with their network can they change router me pls 🙏