https://www.britishairways.com/en-gb...p_and_contacts
The link above should take you to the page with various telephone numbers. So long as you’re logged in and a Silver, Gold or GGL member, it’ll give you the number you’re supposed to ring. Getting through to BA isn’t a big challenge like it used to be. BA Holidays is a separate matter and I believe getting through to them is proving to be a challenge still.