Okay, let me see if I understand this. You filed for a week of unemployment benefits...which means that you yourself, of your own volition, while going to work every day, went on line or called the system and filed a claim, represented that you were laid off due to lack of work, were approved, and got paid? This sounds very unlikely!
Was it a situation of where the company filed for a week of partial benefits, or you filed for a week of partial unemployment benefits because you said you didn't get to work that particular week, though you were still job attached? It also sounds as though your weekly benefit was reduced, probably due to some wages being reported for you. This causes me to think that perhaps this week was reported as partial unemployment benefits by the employer. But you need to ask the unit exactly how the overpayment occurred. If you totally didn't understand how it was supposed to be reported, and it was reported incorrectly for you, this will matter.
Because in the first case, it was outright fraud. You lied, said you weren't working when you were, said you were laid off due to lack of work, when you weren't, you fraudulently filed a claim and the company should have been asked to verify your reason for being off, and this would be how you were caught,( though eventually it would have shown up due to payroll records anyway.) The system cross matches everyone who receives unemployment for a week with everyone who shows up on the Maryland unemployment payroll record system as working for wages during that week. There is zero potential for getting away with it.
But sometimes, when the company or the individual files for partial unemployment, it's due to a misunderstanding of when they are going to be paid or what will happen, sometimes people don't even understand that the claim has been filed for them, many circumstances could be in play here.
Or did you go back to work after a period of unemployment and go on and file for that first week you worked because you weren't going to be paid for it by the employer for two weeks? That's also fraudulent. Common as dirt, lots of people do this, but they never get away with it.
This will all be thoroughly researched by the fraud and overpayment unit. They are your friends right now, though, as they tend to give leniency to those who work with them and are willing to pay the money back and cooperate. Those who ignore them do so at their peril, as those are the people who get made an example of. So talk to them, work with them, and see if you can get this money restored to the system. Whether or not they give you penalties will depend a lot on the circumstances and whether you work with them.
