No batteries for D-Link's DWR-720PW Handset

Telkom use the D-Link's DWR-720PW handsets. These use battery model BL-186-9C. I have two of these handsets. I need to replace these batteries. I went to the Cresta Telkom branch and was advised that they do not carry the battery. But I could replace the whole telephone that contains a new battery. Contacted D-Link to see where I could acquire these. batteries. Was advised that these batteries could be purchased at their offices in Centurion at R50-00 each. However a delivery cost of R100-00 would be incurred if couriered. Poor showing Telkom/D-Link.