Perhaps because DVLA didn't, or say they didn't, receive the letter ED? It happens such a lot
If DVLA think she is trying to get out of paying the tax on it?
http://www.direct.gov...ngAVehicle/DG_4022403
And the op should have also odne this
"If you don't have a registration certificate you can still inform DVLA that you no longer have the vehicle. In order to do this you must write to DVLA, Swansea, SA99 1AR quoting the vehicle registration mark, make and model, exact date of sale and name and address of the new keeper." Which she didn't