ABSA Forex Rip-off!

Purchased British Pounds on ABSA Multi Currency Cash Passort card in June, 2019. Went to UK in July and discovered that ALL my British Pounds had been converted to US Dollars! Every pound I withdrew was charged Exchange Fees, which I paid to ABSA in SA. Withdrew £500 and was charged £145 by Halifax Bank for Bank Charges. Went to ABSA who refused to assist at all and told me phone MasterCard in the UK, at my expense, and sort this out with them! My argument was that I paid ABSA for my £, not some other Bank overseas! Phoned ABSA head office but they are not concerned. To add to this Ripoff £200 has disappeared off my Card when I returned to SA.