MANGO BAD SERVICE & TIME IS TICKING FOR MY FLIGHT

i'm so disappointment with the customer service they providing, Im trying to do a name change for the booking i made before lockdown. but since this pass Monday I went online under my booking to change the name it gives me the R270 payment and when i try to pay that amount it cancels me and says the amount doesnt match it R278 . My problem its right there when i try to change to the correct amount it doesn't allow me to change to the amount given, it gives me the total of R270 AGAIN. I called so many times on their call centre number no one picks up, i complained on facebook they told me to send info on messenger i did that, they telling me to go online BUT THE SAME THING HAPPENS ITS SO IRRITATING NOW. I TOLD THEM TO CALL ME BACK BUT TILL NOW NOTHING IS HAPPENING. POOR SERVICE RIGHT THERE. & IF YOU GOING TO REPLY ON THIS PLEASE DONT TELL ME TO GO ONLINE COS ITS NOT WORKING, CALL ME SO WE CAN DO IT TOGETHER.