Spend Limit being changed without logging into MyTelkom website

My Telkom Spend Limit has been consistently been increased in the course of December 2017 almost everyday from the 5th Dec to the 01 Jan 2018 without me logging into the MyTelkom website. I have been with Telkom for almost two years now and I have not logged into the MyTelkom website for over 10 months now, but somehow something or someone keeps increasing my spend limit. Now my statement for January is R1000 for something I did not initiate. I asked the customer care for an audit trail of all my logins on the site, they say Telkom does not keep an audit trail of logins because of customer confidentiality...really!!!!. So a case was created for me in December and I was promised to be contacted in the next 3 working days, it's January now still nothing. I am very disappointed with Telkom :(