Struggling for 3 weeks to received a refund with a guarantee of payment!

I’ve been struggling for 3 weeks to get a refund which I had to pay upfront to the hospital and the day my husband went to hospital which was on the 16th of March was the same day we received a guarantee of payment. I have emailed and called in countless times and everyone has been giving us the run around! Submit this, submit that! After everything was sent through the first time. They say someone will get back to you in a few working hours but no one does and we have to call in to get answers! Only when we call in do we hear that they need something else or it’s being escalated and sent to a different department! I am fed up and this is unacceptable. THIS IS WITH A GUARANTEE OF PAYMENT AND IM STRUGGLING TO HAVE THEM PAY ME BACK!!