Impossible to get through to Customer Centre on toll-free line

Kulula says on their site that they no longer check Hellopeter reviews so this complaint may be a waste of time. For a whole week, I have spent on average 20 minutes on the phone to the Customer Centre trying to get help re-booking my flights. Either the call cuts off or I hang up in desperation. I phone Kulula every hour on the hour. I've sent 4 emails to their Feedback address asking for someone to call me and haven't had a single response. I had the exact same experience in December. I have never experienced such an appalling booking system in my life and I fly a lot for business.