Any remittance services (salary for helper) that we can use to earn miles?

There is. One way is via Singtel Dash. Singtel Dash allows the remittance of money from Singapore to Philipines. But do note Singtel Dash has a monthly limit of $200. After remitting the money, your singtel bill will be charged $200 you can use your miles credit card to pay for the singtel bill then.

There is another way but because Grab has started to read finance articles/ blogs and shut down cashback and miles hack; my guess is not to lose too much money, I won't post it online for them to know. You can email me. My email link can be found contact me www.investmoolah.blogspot.com

Its not worth the exact costs. These agencies have small profits and if you use credit card, the fee is hidden in lousy exchange rates.

The best remittance are those small agencies in Chinatown, Little India etc that has very little fees and much better exchange rates.

I personally use a small remittance agency at Aljunied MRT station, the rate is way better.