Refusing to change the order after incorrectly ordered the wrong parts

I've Incorrectly ordered the wheel bearing parts at Nissan Melrose after my mechanic diagnose my car as it was making noise while driving . Unfortunately the mechanic find that the car was making noise because the the shocks of the car are the one finished and by the time he realise that it's not the wheel bearing that was causing the noise the payment for the wheel bearing was already prossesed so I call the store to change the order from the wheel bearing I've ask them to order to make it the shock because I cannot have the parts that am not going to use . Its either they order the shocks for me because I don't need the wheel bearing anymore . They are refusing to change the order for me and they insisting that I must take the wheel bearing for no use . I've place an order yesterday on the 27 / November / 2010. Ive paid the full amount of the parts and now I have to throw away the parts as am not going to use it sad

My number Vincent : ***

Ive got to this branch as I was referred by my mechanic that they render good service bt honestly speaking am getting the opposite of what my mechanic told me

I've tried talking to the and this is their respond

[11/28, 9:16 AM] Vincent T: I spoke to my manager now sir. He says we unfortunately cant because it has been invoiced to us by our factory already. And we also dont sell gabriel shocks sir. Only our nissan shocks

[11/28, 9:16 AM] Vincent T: No sir I unfortunately cant change the bearings. The bearings for your vehicle do not sell often sir and we will take a loss on it if we keep them. I can order the shocks for you sir but you will have to take the bearings aswell