It takes time for something that big to register the blow and more time for it to consider a response. Organisations work to their time scale, not to yours. A moment to them can seem like an age to you. It's frustrating, but there's little you can do to change it. Don't be fobbed off, either with something that smacks of a compromise or with something you don't really want or have a need for.
Many companies use their products as balm to soothe complaining customers.
If you would prefer your complaint dealt with to your satisfaction, then don't fall for the bribe. Keep plugging away. The ombudsmen There are around 20 ombudsman schemes in the UK covering banking, building societies, investment, insurance, etc. That's the good news. The bad news is that the ombudsman is an adjudicator of last resort.