To expand on the previous post ... The original flex cables are very rare now, and the supplies of new ones from official sources are probably exhausted. Your best options are eBay or private parties that might have a few.
Even if you obtain a replacement, rewiring it can be difficult - though sometimes a flex cable can be repaired if the break is not too bad.
For these reasons, most people who have damaged flex cables end up rewiring the connections by hand with normal wires.