Failing to pick up fault handset

Beginning of this month, I took out a cellphone contract with the above company. I got the delivery, it was on a Friday, I charged the battery over night, however, the battery dies immediately after I remove the phone from the charger. I called on 09.03.2015 to have the handset collected, up to now, nothing has happened. I have made countless calls and every time I get different days for pick up. Please assist