Why is My Approved Claim Not Being Paid Out?

This company is not being ethical in their claims process. My out of hospital claim was approved after an extremely lengthy process via an Ex Gratia committee. I received a letter of approval from them, but when I sent the details for the claim to be paid out, I was told that the claim was not processed by the PPN. I resubmitted the documents requested, and was assured that it should be sorted out within a week. Only to find out later that they did not intend to pay. Upon follow up, I received a cold shoulder from the Escalations department telling me that the dates did not correlate and that the claim would not be paid. Upon asking for more information, I am being ignored. It appears that they are hiding behind inane bureaucracy to avoid paying out a claim that was approved. I received the approval in May, and it's many months later with still no clarity. I do not understand how they can blame the client and just refuse to pay, I have never misrepresented my case and have all the evidence to prove it. They are using stalling tactics and bureaucratic loopholes to avoid providing a promised service to the client. I am hoping someone could advise me on further action? Is this something I can appeal to the Ombudsman for?