CP58 要上报GST 吗？
That means you have received income under Form CP58 as an agent, etc. Your audit firm is correct and as far as GST is concerned, you have to account for GST under Deemed Supply (DS) since the total amount is above RM500.00 according to Gift Rules.
The calculation for GST Deemed Supply is as follows : RM8,248.00 (i.e. RM7,863.00 + RM200.00 + RM185.00) / 106 x 6 = RM466.87 is the amount you should pay as output tax to Customs.