Not great service

No customer after service. My flights were cancelled after I wanted to only change my flight time. They only refunded me with a voucher I couldn't even use. It gives me errors when I try and cash out. No reply from them after I have sent them an email. Safair please get back to me so we can resolve this. I had to take out more money for more flight tickets and I don't think it's fair. Otherwise you are also a bunch of *******