Mantri apartments are wired for BSNL landline and broadband connection. Wireless router that comes with the modem is however not made available by BSNL at the time of installation. Mr Aashik (9790122995) who helps setting it up at your place may tell you that the router is out of stock at the moment, and he wouldn't be able to tell you when BSNL would issue the equipment. I got mine after a month, this too, after I persuaded PropCare to take up the issue with BSNL.
Till then, you need to tether your laptop with a cable connected to the modem in order to access broadband. The router is that magic box that enables your laptop to access the Net , wherever you take it - bedroom, kitchen, the loo or the balcony.