AVIS Cape Town - don't answer phone calls

AVIS Cape Town International is impossible to get hold of telephonically. My fiance accidentally forgot his driver's license there last week Thursday and we have been trying to get hold of the Cape Town branch since then (with no response). We then had to contact the Call Centre where only an e-mail could be sent. Still no feedback. This is unprofessional service from such a well established company. Not sure why AVIS Cape Town as telephone lines when they don't bother picking them up. How should we go about resolving this issue?