I have had a similar problem. I last filled up about 2 weeks ago in Sainsburys in Godalming. The car broke down on Christmas eve and I now find that it is due to fuel contamination. A lot of work has been done by Citroen to identify the fault and now they have to flush the tank. It will cost probably near £1000. I paid by credit card. I will check with Sainsburys to see if they have had any other complaints and will check with the credit card company. I have a petrol engine and have only put petrol in the tank. The garage has retained some of the contaminant so will have that to verify.