Terrible service

I have booked flight tickets via Travlestart. The airlines have cancelled my one flight due to ban of country. I need to re book or change my flights. No one of Travelstart has contacted me. The whatsapp line does not respond. Email just says they will come back to me. I need to reschedule as my flirst flight is 28 January 2022. The service is terrible. Has anyone else had this issue? Why is there no call centre or phone line?