JETSTAR HOLIDAY BOOKING COMPASSIONATE CANCELLATION ENQUIRY

I contacted Jetstar Holidays 2 weeks ago regarding a booking WHICH STARTS IN 4 DAYS.
I was instructed to obtain a doctors medical certificate and to call back again (easy to say) to get instructions for where to send it to request a compassionate cancellation due to Ill health.
I'v also tried online chat but get told to ring the phone number. All I need is an email address to send the certificate so please can someone help?
I called back last Wednesday and waited over 1 ½ hrs no answer, I called on Thursday for over an hour still no answer, and again on friday 3 times and waited for over 2 hrs.
Today I sat on the phone from 7.30am hoping that I might get through but knowing that you don't open until 8.30am. So I was ringing as soon as the lines were open, yes, I was put through again to Jetstar holidays but I have now been waiting for 40 minutes and no one has answered the extension as usual.
I was a Club Jetstar member until a few days ago but due to the difficulty in contacting them I have not renewed my membership!