intec failed to Cancel my cource worst service ever

i enrolled for a course with them on october 2018 and after a few months i decided i didn't want the course anymore so i called intec to cancel since the 25th March 2019 but ever since they never respond and i called over 20 times already and they always give me the same excuse that they are busy with it till today on the 03 of july 2019 its the worse service i have ever received in my entire life and i just wanted to cancel only.