NonExistent Customer Service! RIDICULOUS!!!!

I've been trying to get hold of Travelstart via Phone (numbers are not active), WhatsApp & email, since Friday (3-12-2021),to rebook a flight that got cancelled by British Airways! It's the 5th today and yet no assistance whatsoever! I need to rebook the next available flight ASAP!!! I've read more than 100 reviews, and I have not come across one good review! CUSTOMER SERVICE IS UNBELIEVABLE!!!