Standard Bank call centres - poor connectivity

I'm calling Std Bank Homeloans repeatedly (***) giving my ID number and contact number each time, and without fail the connection to the consultant is AWFUL: Long gaps of silence, I cannot hear the consultant, they cannot hear me. They never call me back (since I provided my number).

No doubt this is one way to assume that no communication equates to no concerns. How else do I resolve my Std Bank queries, apart from sending a letter via SAPO?