Travelstart service is falling apart & I am stuck without a paid return flight

Hi all, this review form does not give minus-stars so Travelstart gets only 1 star. I have a return booking with them which includes to change my booking within 24 hours from my flight times. So on 6 April I completed their online flight change request form +/-26 hours before my return flight 7 April 2022. I tried the Whatsapp and the phone number option to get confirmation with no success. Their Whatsapp bott keeps giving me the phone number and the web form link. Their phone just keeps ringing / playing music for 2 hours till you give up. Even on Facebook they just give you the phone number to call. No reply via email other than an automated ticket number. I emailed and tried phoning several times for feedback. Only on 13 April I got an email and they say I already flew with my flight on 7 April which is totally untrue, I did not even check in because my change request was made on time & I had their ticket number. On 157 April they let me know that I have to contact the airline of my flight to arrange the ticket change. But this is nonsense because since I started doing all my flight bookings in 2012, I used their change flight service several times and it never worked like this. They ware also very prompt to respond to these booking change requests. I still do not have a new flight time for my requested return flight 4 May. Is there anyone that can PLEASE assist me to get this resolved?