Personal Details changed without consent

Ive been fighting Telkom for over a year to get my account details sorted out. Im losing 5 days a month without internet. According to the technical department, the sales department has changed my personal details on my account and have replaced my phone number with another number unknown to me. Once a month i am forced to reset my password due to technical errors. When i reset the password i receive nothing on my number. According to technical there is another number listed as my Password reset number. The sales department denies any responsibility and forwards me to technical, who them revert me right back to Sales. This has been an ongoing issue for close to a year now and no one is willing to help.