Flat building access

CMT4a

Hello - I am looking for some advice/help to point me in the right direction please.
I am a quadriplegic who uses a manual wheelchair and am living in a 2 bedroom flat and privately rent it but I have issues with access. 
There is a main front door that is too heavy for me to open, both from inside and outside the building to get outside. I contacted the people in charge of the building (Centrick) and they made the fire door around the back of the building my way of exiting and entering the building to get to my flat and a key fob that opens the door. The problem is to access the door, I need to go up a steep short hill which is dangerous and due to weakness I can not get up this hill to access the door, and risk tipping backwards when I have tried pushing my wheelchair up it, also the door opens outwards so its even more difficult to use the door, also there are flower beds on each side of the hill - (Like a deep step on each side of the hill) where if my wheel falls in to the flower bed then I am stuck. This has happened to me a few times and I had to phone family to come and help me.
I complained to Centrick about the fact that the front door would be easier for me and asked why they couldn't make the front door electric and they told me it is too much money to do that and so they won't do it.
I have been stuck indoors now for 3 years and do not know what to do and I have been depressed and also told all my concerns to my occupational therapist but nothing came of it as she said she can not deal with anything outside of the actual flat. I feel I have been imprisoned in the building and it has affected my mental health, I literally pleaded with Centrick but they said the back door option is the best they can do - This was about 3 years ago and I had to get a solicitor involved for them to even do that as they kept fobbing me off.
Because of depression and feeling hopeless I have just given up and spent the past few years indoors as I feel nobody will help and do not know who to reach out to. Can anybody advise me on what I can do please??? I would really appreciate it. Thank you.

CMT4a

I forgot to add the steep hill is narrow so there is no way to turn the wheelchair either and one wrong move can either tip me backwards and cause injury or I can end up stuck in the flower bed on the side. 

woodbine

The OT is probably right nothing they can do inside your flat when you don't own the building, is there anyway you could move to somewhere more suitable ?

CMT4a

Hi Woodbine - Thank you for your reply. I am on a housing register but it is for 1 bedroom and nothing suitable has come up. Also when I look at private renting, it is too expensive as I need a 2 bedroom as I have a carer stays but the council say the carer does not stay enough nights to qualify for a 2 bedroom.