Pantel Technologies Pvt Ltd — refund not given

Address:

Mumbai City, Maharashtra

MY booking id. is:PENT0097894. i have received my tablet in the month of may. but i haven't received the Sim card to which they charged rs. 250 extra.
When i asked to them through their customer care service, they said the company would refund the money through cheque but i haven't received it yet.
when i do call to their customer care no., it always show they are busy. Actually they pick up a call one time and then they block or save the phone no. so we cannot contact them.And i have to try from other land line no. so they pick up the phone. please help me out.