Change of Booking

I tried to change my flight from the 3 Jan 2021 to the 6 Jan 2021. I only wanted to change the date. I had booked a refundable flight with extra check in baggage. After changing the date my baggage was completely removed. I cannot add extra baggage and my flight is now non refundable and cannot be changed. There is a reason I booked a refundable and changeable flight and a reason why I paid for extra baggage. Why would I change any of that just because I wanted to change the date!!! I am extremely furious and I haven't even been able to get through to any department. I want my original flight options which is what i paid for, for the flight on the 6 Jan 2021.

No one has even responded to any calls or emails and it is impossible to get hold of anyone for assistance!!!!!!!