A foreign lady keeps stalking me and Idk what to do about it

I recently joined this online dating site. I first got matched with a foreign chick from Colombia but later cut things off when I realized she and I have nothing in common. Then later on, I got matched with my now girlfriend. Weíve been together for about 2 months now but that Colombian lady still bothers me. She even goes as far as checking my posts or chat me when she sees Iím active on the site. Iíll be leaving the site for good since me and my gf talk mostly through skype but Iím just waiting for her to have stable internet connection at home. I honestly donít know how to handle the Colombian girl. Iíve explained to her that Iím no longer available but sheís been very persistent.