Load of rubbish

So I got a travel card for traveling south east asia and I load my card with thai baht but when I lift money out of atm it converts back to gbp then back to thai baht which costs me alot more.also for transactions the post office charges me £80 then £1.50 with other charges that I dont understand as the amount I lift including the atm fees alot more gets added on the overall withdrawal which must be a fee of some sort that I have not been made aware of then also transaction fee on top of that. I would not use this travel money card again for travels as its just a way for them to take alot of money of you