If you're phone is an Android-running phone, that's weird. This is because the pre-installed browser provided by Android had the (almost) best features available such as Javascript and HTML5. If it's a non-Android phone, just update the browser or find another browser that can substitute the old...
Re: How to get this serial number
Dude, get your PC connected to your wireless network, type 192.168.1.1 at your browser (I don't care what kinda browser ya using, all of them are OK) and set/change the password of your wireless network.
Technically, it's not the problem of your phone. Try check your call settings your call divert settings on your Dialer, or try call you carrier's customer support for the configurations on ways to configure them to your cellphone instead of your voice mailbox.