Now is not the time for entering this business. if it was 2004-2005 then yes! but now its too late. the market has saturated. there insnt gonna be any new (first time) customer and telco companies are divesting these days, trying to minimuze cost and squeeze out every penny from everywhere they can. so, stay away from this business.
Secondly, the profit margin is also very low. literally in 0.xx rs per sale.