Hotpoint Iced Diamond RL63P fridge door problem

Fridge in question: Hotpoint Iced Diamond RL63P

Sometimes the door just won’t close you shut it and it just springs open again, you can feel the resistance at point of closing. I put it down to the light switch on the inside if I press it manually and let go and then close it it closes fine. My mother thinks its because the door is hanging, you can see its slanted, which also makes sense but my method does the trick. It’s been fine so far though.

Ultimately I think it just doesn’t have very much suction when closed so the light switch has enough force to open it again. I would just let it slide but my mother wants to replace the fridge, I said to wait until it breaks down at least. I wouldn’t mind fixing it myself if there is a solution as I don’t like the idea of sending a working fridge to the fridge freezer grave since they can’t be recycled right? The fridge does keep things cold but I think it might be working harder than it needs to.

Hope theres a solution, thanks