Pathetic customer care

I need to make urgent changes to a booking I made a month ago (flights are next week). I tried to do this online but could not. Tried numerous times to contact the call center on the number provided on website. No operators answering the phones (all calls I made, and made to wait, was 10 minutes plus). Send an email to call center informing them of my disgust and requested that they call me urgently. After 24 hours, still no call.