Can you give them one more chance but explain that if you pay does not go in tonight that unfortunately you will have to go to the ombudsmen. That way you have warned them and been completely professional about it. It is not personal it is professional.
I have sent an email this morning, saying that it is still not showing in my account and if I don't have any advice that someone will be going to the bank when it opens, or proof that it has been put through first thing this morning, I will be taking it further.

I am going out with the kids this morning, but they don't know that, so they do have a few hrs up their sleeve before I do anything. My husband called them yesterday (I was a bit fragile after getting my wisdom teeth removed), and got the run around as well. He told them yesterday that it would be going to the ombudsman. So I have given them their final chance, if nothing by lunch time when I get home, I Will be making the call.