You could contact both the OnePass and SkyMiles service centers and say, "hey, these miles were supposed to post to the other account. Will you deduct them from this account so I can request credit in the other?"

I've done this once when, despite a CO # in my DL record, the miles posted to my DL account. DL removed them, leaving big red marks on my account activity. Them after sending the BP & receipt to CO they posted there in a few days.

It's doable, but patience is necessary!