So my unifi installer finally setup unifi lite 10mpbs while i was not at home(under my mum name btw,but i manage the home network),they manage to setup the wrong password provided by me,i cant find any information about tplink c1200 pppoe password recovery(because i want to change the router to a better one)so my question is:

1.how to retrieve pppoe password from tplink c1200(search around only got dlink and older model tplink router which is not work for newer model)
2.if all else fail i call unifi hotline will reset the password or just give the existing password?(unifi have to up all the time while im not around otherwise i will be questioned by familly why unifi down)
3.are rt-n18u good enough to handle 3pc constant streaming of data?i dont need ac router.might upgrade to 50mbps at future

Thanks