I'm sorry you had such a reaction. I found, that for me personally, true detachment didn't come until a fair amount of time after no contact - months. I still have 'moments' but it does not throw my day/life off like you describe anymore and the intense physical reactions are not there or only very fleeting. I suspect most people have moments.
Detachment came for me when I became more clear on my own needs and that I was truly responsible for my own needs. No one else was, and I wasn't responsible for anyone else either. I totally relinquished the idea that I needed to (or even could) do something to fix their (xah in my case) life or to lesson their discomfort and unhappiness.
ETA: There are ways to block specific numbers from your phone so you don't have to get a whole new number if that is a problem.
Just read noday's post. Yes - I forgot I did a lot of that. I said the Serenity Prayer and then really asking myself whose problem is this exactly. I had to really examine things to figure that out. Usually it was not my problem after closer examination. Say Serenity Prayer again!