Problems with recent battery purchase

Hi,

  I purchased a replacement battery for an Acer laptop from you on Wednesday and have a number of problems. The battery I purchased was "SQU-519 916C4820F ACER ASPIRE 3634WLCI 3630" which has a part number of "BT00407007622015922501". However the battery I received has a different part number "BT0060301662102ABE2500", a different voltage (11.1V instead of 14.4V) and a different ampage (4000mAh instead of 2000mAh) - in short an entirely different battery. The batteries do look very similar, and have identical pin arrangements but are obviously completelty different internally.

  Please advise how I go about returning this battery and obtaining a refund, or swapping it for the correct model.

Regards,

  Paul Tassell.