Poor customer service

Norman Bissett keeps on sending me e-mails that I owe Glocell money. I have called them and spoke to a lady by the name of Alicia Malaza. She assured me that she will look into this and get back to me soonest. I have been mailing her and calling for feedback but there is none . I explained that Glocell was billing me even after the the contract ended . There was noone I could call and I even put them on social media to advise them to stop billing me. to no avail . My reference is ***6. Can someone give me some feedback .