high exchnage rate

I withdrew the money in March of about 30,000 usd. by octafx, my funds are partially required to return to a credit card of 19,955.98 usd. I asked if I still can send it to my bank. but if that's the rule that must be done, I'm fine.so the rest is sent via bank transfer. and my money came in at the current exchange rate to my bank.but what really problem is what goes into my credit card. Other brokers use the current rate when returning to my credit card. from us dollar to IDR rupiah.but octa fx uses the exchange rate when I make a deposit. where the rate is lower when sending to a credit card time. deposit in late january and early february. so if using the exchange rate at that time (march), I did not receive USD 19,955.98. but rather around USD 19,000. because of the difference in the current exchange rate and the time of deposit.