Bad attitude and lack of knowledge

Yesterday I call center and my call was dropped.... usually when that happens with other call center companies they call back. Today I call back and with the intention with signing up with a mobile device product and the agent is NOT CLUED up with the supporting products that will make my mind up whether I would buy the product or not. I ask whether I could speak to a manager..... she keeps me on the phone for long time and then she abruptly tells me I must call back the manager is not available because he/she is in a meeting...... then who assisting the clients? Or why not offer to take the clients number and offer to call them back when someone is available to assist?