Suggestions to buy Nexus 7 motherboard

Wondering where to buy the motherboard for my Nexus 7 ? Tried ASUS and after 4 different calls to 3 different numbers they finally came out and said they can't sell me a motherboard. They are not for sale. They want 202.00 to service it. For that I can just buy another one. Good customer service ASUS. That'll be the last product I buy with their name on it. Googled it and all I find is how to repair, not where to buy.

Any help ?