Avios booking for a gold member amend or cancel advice needed?

[Wing It One World]

I currently have a booking to YYZ and sadly now need to change the dates and location completely, I have attempted to speak to BA but I sadly needed to go to work after holding for 55 minutes ( gold line)

What are the best options available to me please?

Twitter is quite helpful but They want to charge me a fee to cancel completely( I thought as a gold it was free).

Am I able to just change the dates and location as a change booking rather than cancel and rebook and pay refund the difference of avios points?

Thanks

[NorthernLass]

Have you checked in MMB to see if you can change it yourself?

[Wing It One World]

it allows me to change the date / time of the flight not the location.