Regardless of the technologies involved, must say I support Stuart in making the complaint. So many organisations these days seem to think they have no obligations for customer service, as long as they have a complaints procedure. So why not let's use it?
I have invoked formal complaints procedures of ISPs, Insurance Companies, Pensions trustees, GPs, and more, never regretted and it and even had a few good outcomes. Brits are often criticised for not being good at complaining, we suffer in silence until Things have gone too far and even then we don't complain, we just rant and rave.
And in cases such as ISPs and CPs with outsourced Indian helpdesks, if enough people invoked the complaints procedures, it might must cause enough grief for senior execs to force them to admit, things ain't working.
Good luck, Stuart.