change from o2 to smarty

hi,i already have smarty unlimited wifi £20 been great been using for months now,so i just gave smarty my o2 number a pac to change the smarty number to my o2,i need the full access of calls and txts and unlimited wifi for £20,my smarty sim only does the wifi only,so when this change takes place,can i still use my number for calls/texts  or does that just mean iv just changed my o2 number to wifi only sim card,i need this number as iv had this for years so need calls and texts or should i use the cancel process,i can phone smarty as im broke,so needs to be responce on here.ta jim