I will give you all the support I can Bex, don't like to see others suffer, because I know how it feels

Well, I'm going to give advice here, but know that I am not a qualified psych, or qualified in any way apart from being able to relate to you.
Now, I was an addict, not to alcohol, but to cannabis (for 11 year).. and no matter how many times I got told by people to stop doing it, that I'm damaging myself and those around me, I refused to listen. I blanked it out because my addiction was too great, to powerful to listen. Then guess what happened? I lost those around me, my health declined, and I lost my family (there were other contributing factors also). This was a wake up call, I had lost everything through an addiction, and I only realised when everyone around me disowned me..
Now I'm clean, I've been clean for about 2 months, and slowly but surely, those people are coming back to my life, I suppose in a way "you never know what you had, until it's gone" couldn't be a more accurate saying, I learnt from my mistakes, and as cruel as it sounds, maybe your mum could too?
She still sends you money, so there is still thought for you in there, she still knows that there is a bond there, and maybe she just doesn't know how to appreciate you? maybe she needs to realise what she is missing out on? (now remember, this is a suggestion, and I'm sure there are many other alternatives, I'm just speaking about what worked for me to open my eyes).
I know you've tried these steps, but you must have just a little bit more push with it, it'll hurt the pair of you, but maybe something better will come from this, maybe your mother will come to you for support for you to guide her through this. Just let her know, that you are there for her if she decides to go clean, because she will need you.
Like I said, always try to find different methods, but as a previous addict, I know how hard it is to just give up, I ran my life into the ground because of it. No matter what course you take, I'll still be here to talk if you need me Bex, and I hope your Xmas is going to be a good one this year =]