Maternity and redundancy

Hello everyone, I have been working part time with a company for the past 5 years. Last year when I was pregnant we got told that a reorg was taking place and we were all at risk. When I was away on maternity, I was told that my role was at risk, and I could apply for a new role if I wished. I applied for it. After a few days I got a call from HR saying that they had taken legal advice and that I would automatically be given that role. I was very happy and said yes to the role. After a few days I got a call again and got told that this was a full time role and as it was a new role they didn't have to meet my hours requirement. I was given time to think and get back to them. I said yes again. A few days later, I got the appointment letter for the new role. Unfortunately, things on my personal front have changed and we (family) have decided to move to a different city. My employer agreed to let me work from that city. However, I am now not very sure that I want the role any more. I think it will be difficult for me to cope with the role in a new place. I went back to HR and said I didn't want the role any more. I have now been told that as I am now refusing the role it will amount to resignation and I will not be entitled to any redundancy. I will also now have to return the enhanced maternity pay I received from the company. Please can anyone advice me about my situation?