Just recently suffered a bereavement and have been trying to contact Thames water all morning (phone and we chat) Forgive the humour but I feel I might die of old age myself waiting for the customer service line to answer. I dealt with them on a similar subject a few years ago and back then they had a dedicated team who were really helpful. Basically I have requested a callback. Let's wait and see.
I agree that this is totally unacceptable too. The number mentioned in the post is not a dedicated bereavement line - I've been on hold for 10 minutes on this number and it hasn't even mentioned bereavement but has offered hints on how to save water - slightly too late for my father who has passed away. Thames water really need to be more sensitive like the other service providers I've contacted who genuinely do have a more sensitive dedicated service