I had a similar thing happen on a motorway that smashed my long TDI undercarriage covers.
They are easily replacable, the studs are in the chassis and the covers come with integrated plastic nuts to tighten on these studs.
They are about £40 from a dealer or TPS. Don't waste time with used as most have cracks.
To put it in perspective, I just bought an R32 engine sump cover from a dealer and it was cheaper than buying a damaged one on ebay.