Do you think it is reasonable to extend the end time of the auction the same amount of hours the auction has been "closed" by a mistake?
Only the auction wasn't closed, you had ended it (in error, indeed).
There really is no standard procedure for these errors but I'd think in this case you're going about it right by notifying & giving all parties a fair chance.
I got the feeling no matter what happens, someone is going to be upset. There doesn't seem to be any version to fix this error that is fair to everyone.
If the OP stands to his mistake and honors the (arguably wrongly) announced auction wins, teeGUMES might be upset about not getting the chance to bid on these.
If the auction is opened again, we might see a bidding war and the original winners (yes, that does include me) are out of a good deal that was already finalized in most parts.
Now you're very new on this forum and your actions will decide how people perceive you and interact with you, OP.