I don't speak Bengali but it happens I am able to read it. This word is used throughout South Asia and belongs to English vocabulary as well (see challan). Normally it means 'an invoice for a fine' but other meanings are possible, according to the context, which I can't understand.
Yes Marrish is perfectly right.
Just to make it complete, "chalan" has another meaning (not applicable in your context, though): "transportation (of goods from one place to another)", used mostly in the collocation "chalan deoa" (চালান দেওয়া) = to send/transport/export (goods to another place), and in the derived word "chalani" (চালানি) = imported, transported from another place - very commonly used at the marketplace to indicate nonlocal produce.
Then there is also the verbal noun "chalano" of course.