Intel Mac :: (Mid 2010) Memory Bank Was Already Damaged Before Bought It?

I use my Mid 2010 iMac for virtualizing routers. I noticed that with the 4gb of RAM that was already installed in the iMac was not enough. So, I did some research and found out that, my iMac can hold up to 16gb of RAM. I did some more research and found out how to replace the memory in my iMac. Then, I went to Micro Center and bought 16gb of RAM and brought it back to my apartment. Now, I powered off my iMac and unplugged the power cord, flipped the iMac upside down and unscrewed the three screws that were holding the memory cover on.  After removing the memory cover, and pulling back the memory tabs/flaps, I shined a light down in the memory slots and found one memory slot that looked damaged. I was not completely sure, so I went ahead and removed the old memory by pulling hard on the memory tabs/flaps, and the memory was unseated.

I remove the memory and replace it with four, 4gb sticks of memory. Once I powered on the iMac, a memory beep sounded off. So, I unplugged the power cord from the iMac and removed two of the four memory sticks out of the iMac. The two sticks of memory I removed was out of BANK 0/DIMM0 and BANK 1/DIMM0. BANK 0/DIMM0, is the one that is damaged and my hardware warranty has expired. I bought this iMac damage, and now it won’t support 16gb of memory. What should I do? By the way, the other 8gb of memory in the other two BANKs are working.

Info:
iMac, Mac OS X (10.7.4), Memory BANK 0/DIMM0 is bac