Hero Electric — Dual battery change over switch not functioned

I bought two days before Hero Electric OPTIMA HX S12b model at one of the showroom at Chennai, Tamilnadu.
One of the battery completely drained, to connect the another battery (fully charged) by using change over switch advised by agency representative.

When situation rises, i tried. it was not working. I have given vehicle to show room for attending the issue. They felt difficulties to resolve this issue.

I request HERO ELECTRIC company to facilitates the Service engineer well trained for getting back the vehicle promptly. Otherwise this leads to dissatisfy with customer.