Make it as hard as possible for customers to contact you

Discovery Bank has good products and a fantastic reward programme. However, I need to query why interest was charged to my credit card account, which I settle every month, and the only way to contact the bank is telephonically. Why must wait on hold an agent - why can't I log a request via email or via the app? (This same situation applies to Team Vitality, where I have to hold for 45 minutes to speak to someone. Ridiculous.)