Overpayment notice from edd?

I sent in my edd ca claim form and the next day I received a notice of potential overpayment. The first two weeks were due to I was training and I did not know we were not paid and I was not made aware of it until two weeks after my original start date. The others were dud to I was called in after my claims were sent in. The rest were dud to mistakenly not reporting Overtime. I explained that this was not done intentionally but I ma sure I will have to repay. I received my check but I am not sure if I should cash it until I the determination is final. I still have over $4000.00 left on my claim for this period Will I have to pay it back? Will they offset from what I have left from benefits?