AFAIK there's 3 failsafe,
1st, login password,
2nd, daily transfer limit (default is RM100 per day only, and cannot increase online)
3rd, TAC to mobile phone

So assuming the password and registered mobile number are still the same meaning account isn't changed/reset... the daily transfer limit has to be 2k+ to allow the transfer.
Did TS use the account for business transaction purposes? Why leave such account setting (with 2k daily transfer limit) without using it for some time? And why TS doesn't use your own mobile number?