clairelj:Is there anything I can do (apart from this!) when a company just won’t respond to complaints about service?
Just noticed your post. To answer your question, possibly.
It's not always realised that to just to be ignored is sometimes a good outcome. You are entitled to ask the telecommunications ombudsman Otelo, to investigate any complaint where you remain dissatisfied 12 weeks after first raising the complaint. Since you have an email acknowledegemnet that will be easy to prove.
Can't say whether it falls within the Otelo terms of reference, consult the Vodafone code of practice and enquire of Otelo. If the case is accepted Vodafone will be hit with a hefty case fee regardless of outcome, costs you nothing.