Still waiting 3 weeks on

On the 17th of January, 2016, I finalised an order for a new laptop battery. Proof of payment was sent and acknowledged. I am now waiting for an estimated date of delivery and have received little communication apart from being told that they are waiting for the vendor. I have emailed again asking for an estimated delivery date and have received no reply. It is not acceptable to have to wait this long for information on when this part will be sent.