  We report a single-crystal neutron diffraction and inelastic neutron
scattering study on the spin 1/2 cuprate Cu$_3$Bi(SeO$_3$)$_2$O$_2$Cl,
complemented by dielectric and electric polarization measurements. The study
clarifies a number of open issues concerning this complex material, whose
frustrated interactions on a kagome-like lattice, combined with
Dzyaloshinskii-Moriya interactions, are expected to stabilize an exotic canted
antiferromagnetic order. In particular, we determine the nature of the
structural transition occurring at 115 K, the magnetic structure below 25 K
resolved in the updated space group, and the microscopic ingredients at the
origin of this magnetic arrangement. This was achieved by an analysis of the
measured gapped spin waves, which signifies the need of an unexpected and
significant anisotropic exchange beyond the proposed Dzyaloshinskii-Moriya
interactions. Finally, we discuss the mutliferroic properties of this material
with respect to the space group symmetries.
