The merchant description is BIG C -HANGDONG 2Aê´â¯Å (þШèÍ)CHIANGMAI10330 THATHA, as you can see there are Thai characters in the description which is why the checksum is failing. Please can you amend your checksum calculation to include Thai characters.
The customer tried a transaction on the 5th of May for ฿303.75 at BIG C -HANGDONG 2Aê´â¯Å (þШèÍ)CHIANGMAI10330 THATHA, this transcation was then reversed. Even though the transaction was reversed the merchant still settled the transcation. Tutuka have processed a chargeback with MasterCard to have this transcation reversed. The chargeback will be completed on the 6th of July as it takes 50 days to be nvestigated by MasterCard.
In the meantime however Tutuka needed to get the card balance back to zero so that the customer can still use their card. Since the card was in a negative ฿303.75 due to the incorrect settlement Tutuka sent True Money a deduct adjustment to get the card balance out of a negative.
If True accept the adjustment the customer will be able to use their card. After the 6th of May, if MasterCard finds that the merchant was wrong by setteling the transcation they will revrrse the settlement. This means that the customer will get a refund of ฿303.75 after the 6th of May.
Please can you accept the deduct adjustment in the meantime so that the customer can use their card.