compliant of poor service and communication

The Worst experience ever, I am never again booking with Travelwings, I sent an email to change my flight booking and nothing happened as it was a nonrefundable ticket, i called and couldn't hear the agent properly, i had asked him to send me details for the costs of the change in booking via email, he didn't, now when the flight boarded and i called the next day, i was told it's because i didn't call back, then they made me wait for 5 hours without getting back to me if they could assist me or not, it was my first and definitely last time dealing with them