Not trustworthy

My son was asked to participate in the shoot for "Kom Ons Braai" . He is a student and lives from an allowance from his dad's - who has passed - Trust fund. All went well and the shoot was done. A Month later they notified us they lost the memory stick with the contents on and the shoot has to be re done, - we were told at their cost. We paid for all the food, drinks and all. Now we are battling to get the payment from them for the additional expenses we incured