The phone line you currently use is connected to a large Telco's exchange. That's what gives you a dial tone and all the other services that you use with your telephone. This connection also comes with a Monthly Line Rental Fee.
If you only use your mobile as your primary telephone number and only pay your Monthly Line Rental Fee to have access to internet, then a Naked DSL service will enable you to disconnect from the big Telco and be connected to the world through Vintek Broadband.