I had a similar situation in Malawi last month - there's a local limit of around £50 and I needed a lot more than that. My first two transactions went through but the third didn't but I got a receipt saying cash retracted account debited so my UK bank is refunding the charge. I travel extensively in developing world for work and don't normally ask for a receipt but this has taught me to always get a receipt. Good luck in trying to sort it.