What could be a possible next step after a bachelors in Economics and Business Administration?
I can think of a couple of options off the top of my head:


Apply for a Masters in CS anyway and see how you go, you might get credit for your experience.
perhaps do a postgraduate certificate/diploma in CS (if available) and use that as a stepping stone to the Masters degree that you desire.
Perhaps consider a MBA that has a strong focus on CS (as a major).


It would also depend if you are intending to pursue your proposed Masters by coursework, research or as a mix of the two.