Hi @kixsh! I assume your current plan is the Best Ever Superplan 1799. To answer your questions..
If in case you want to discontinue your line (meaning have it cut), you won't be able to use your number anymore of course. But if you mean by not continuing is to not recontract, your line will remain as it is.You will still be charged 1799 a month plus overhead expenses if any.
If you plan on re-contracting, you can either 1) retain your old plan but not get a new phone; 2) get a new phone with a lock-in period of 24 months but you are subject to a change of plan from Best Ever Superplan to My Lifestyle Plan (MLP); 3) avail of the bill rebate. Since you said you are a heavy data user, you may opt to choose GoSurf 799 (5GB) or GoSurf 1799 (10GB). These data allocation will be added to the base plan of MLP of 499. There are a lot to choose from the MLP packs depending on which apps you use.
You may want to check this link for more details: http://www.globe.com.ph/mylifestyleplan-info