Best Buy review: didn't let my transaction go through

We were purchasing this particular iMAC on the 14th of September which was the last computer in stock.
Apple iMac 27" Intel Core i5 Quad Core 3.5GHz Computer With Retina 5K Display (MF886LL/A)

These Asians commission hungry low life Sales associate name on his tag was (Mohammed) thinks they can outsmart us. Because I refuse to take the extended apple care service from them he didn’t let my transaction go through and pretended that my card didn’t have sufficient funds.

I used my Visa at one point and then used my Debit which did already have sufficient funds to make the purchase. This is mainly to all customers that go to the Mississauga Best buy HEARTLAND TOWN CENTRE, 6075 Mavis Rd #1, Mississauga, ON L5R 4G6.

I will be taking this further in to all forms and social media. This is not right and needs to be stopped.

Exact date and time of incident: 9/14/15 time 8:15pm