There are plenty of ways intelligence/police can counter extortion.If you own a business and don’t pay tax to Al Shabab, you will get killed. How can Benadir state stop that?
Attacking taxmen who come in person, dummy corps or a dummy manifest, attacking tax checkpoints or atleast tracking them, monitoring data out of telecom/mobile banking companies, etc
The higher hanging fruit require the NISA but since its run by Mahad Salaad I wouldnt hold much hope in that direction.