Mweb poor website service

Every month I have this problem with mweb. When I purchase a voucher I don't get an option to cancel it when I haven't received a notification to approve it. The worst part of it that they are not operating on weekends which is a major pain. Cause I have to call them and wait in a long phone line for someone to answer me. After someone is available and transfers me I get disconnected and end up back to the main menu. Why don't they have an option where you able to cancel these pending vouchers? As an ISP they should be hands on 24/7 and not from 8am to 5pm. Now I am sitting with a problem which I have to wait till Monday to try to resolve. Why don't they create an app in the phone store like every other company to make their customers life easy?