Read the text below:
"Dear Customer Service,
I recently purchased a 'SuperBlender 3000' from your website (order #SB20230510). Unfortunately, after only two uses, the motor stopped working completely. I followed all instructions in the manual, but it made no difference. I am very disappointed with the quality of this product and expect a replacement unit or a full refund, as this product is clearly defective."
What is the customer's primary reason for contacting customer service?
A) The delivery was delayed.
B) The product was too expensive.
C) The blender's motor stopped functioning.
D) The instructions were unclear.
E) The color of the product was wrong.