Went to UMobile CS center and asked for open complaint report, the CS over the counter also no idea where the message sent out and what is the purpose.
Wait for almost one month over then just received call from UMobile CS.
they have waived the two SMS charges and blocked 66668 to send me any message.

as i did not tie up credit card to any platform, so nothing loss other than the rm0.15 sms fee.
Feb, May, July also received such sms. I think already 3 sms from 66668.
logged report to umobile center and they refunded the money since they cannot track where this number from, also the source of sms.
they also promised to block this 66668 sender to send any msg to me.