Looks like the GA may not have followed CO protocol.

CO downgrade protocol is very customer friendly, and they are to solicit volunteers for the downgrade (and offer compensation + fare difference), and then downgrade involuntarily in reverse upgrade order.

It's difficult to believe a Plat on an A fare is one of the first four (4) to be downgraded.

Anyhow, you should have received a voucher based on the distance of the flight.

The CO profile to reference is GG OVS DOWNGRADE, and IIRC SFO-CLE should net you a $500 CO voucher.

Next, CO is supposed to give you a refund of your fare difference between your fare and the lowest published economy fare available on your date of purchase, so that's quite a bit of a refund possible depending on when you bought your ticket.

Did they at least compensate you according to policy?