AVIS branch at Bram Fischer does not pick up phone

Please can someone explain to me how I should contact a business when they NEVER pick up the phone? I looked on the website, there is no e-mail address listed. And on the 8th and 9th of June 2015 I phoned them constantly, and not once was a phone call answered. That branch is HIGHLY UNPROFESSIONAL, as the OR Thambo branch picked up every time I called there. It is disgraceful that a small branch such as Bram Fischer is apparently too lazy to pick up the phone, when a busy branch such as OR Thambo has time to do so.