should i upgrade my plan or router

i have bsnl 50 Mbps plan pc with ethernet , 1 tv and 6 phones in wifi. ost of the time all devices are connected but my phone can't get more than 2 Mbps even if other are not connected I checked it with other wifi not the problem of mobile I use the default bsnl net link router is it my plan or router

also when I try to sign up in self care portal it shows north circle .there is a bullet msg saying south and east has new portal can't find it