Poor Telkom customer service

My sim only LTE Telkom contract is ending in July and I want to cancel my contract with them . I went to telkom Jubilee Mall in May to give them my 30 days notice, I was told to call telkom as cancellations are not done at the store. I called 081180,the consultant said she's transferring me to cancellation department. I waited for about 30 minutes on the phone without any help. I went on the website (telkom app) to request a call back, to date no one called me back. How should I contact Telkom cause it's really a hassle to get help from them.