Very Slow internet Speeds

Rain has become very very slow lately. I am working from home and always have connection issue. THere can only be 1 device connected to the internet the moment a second one connects the internet bombs out. i am getting below 1mbps when i do a speed test. I have logged a call on my dashboard and i have sent a message on whatsapp but Dololo Rain. I wanted to upgrade to the unlimited package but heard that is even worse.Please explain otherwise you will lose a customer.