As others have stated, would only message when all other options have been exhausted. I am always puzzled to hear people struggle to get the help they need via the phone lines. I almost always have been able to get through with little to no wait on the silver line and even though it's usually the Indian contact centre, being polite and patient I have had my issue sorted every time bar twice. Both times were in the 'COVID' era and for one of those I was able to get the issue sorted by emailing Sean Doyle (exec team) and the other I did message the refund helper here (after calling multiple times and using the complaints form) who sorted the issue quickly.

If you can call between 9am-noon and 2pm-5pm UK time, there's never much of a wait IME.