The same thing happened to me and so I fabricated a fix. I took an old cartio tube thing ripped it apart and drilled it out (so the protank atomizer will fit through it) and ground the back side down flat, then I took a die grinder tool and made a indentation on the pro tank base for the new thread piece to fit in(if you don't do this the threads would be too long and it wouldn't make a connection. Once I had it all lined up I shoved a piece of rubber in the base where the atomizer screws in( so I wouldn't damage them) and then a soldered the two pieces together. So it seen stronger than it was originally and vapes great! It sounds complicated but it only takes 30 to 45 minutes. If u want to do this and have any questions let me know ill try to help if u want any pics ill try to post them