Are they doing legally? Burmese money remittance services from Peninsula Plaza.
If not why authorities close the eyes?
There're alot of remittance service counters/companies. They operate by license from MAS (monetary authority of Singapore).
The purpose is for workers to send money home to their country/family. Its nothing illegal, as long they have license from MAS. Its to send money home...why else do you think the foreign workers come here for?
If you have reason to suspect they are doing anything illegal/no license, call MAS and give them the information. If its true, MAS will then ask the police to take action on behalf of them. The police doesn't go around checking such - its not their duty.
How old are you, by the way? Remittance sercices are perfectly normal and legal.