There are some situations where a refund would be due. For sure, if you end up in E-, that is one reason a refund would be processed (this would possibly happen in the case of an aircraft swap or irrops). Other reports have said that if you have bought E+, but get upgraded (i.e. applied for a mileage upgrade, etc. and get it) that they have been refunded also.

However, I don't think earning status after buying an E+ seat is a reason a refund will be given. I know this is definitely the case for the annual E+ option.