I think you and your family members have been too soft and your Filipino maid is taking advantage of you.
Try to start off with something like :
"I called back yesterday afternoon but nobody answered the phone. Then I called again 15 mins later and again and again for xxx mins. and still nobody answered. Where were you ?"
If she said she went to this place and that place to buy this and that, you can follow up and ask her :
"You only need to take x mins. to walk to this place, then another x min. to come back..... Altogether it should have taken you at most yyy mins. Where were you the rest of the time (30 - 60 mins)??"
And follow up from there with your composition / comprehension skills, e.g. "and aaa and bbb all told me that they saw you chatting with your friends for at least xxx mins., not once but many times, and you were chatting from the time they entered the market until they left. I know you have a lot of friends but ....."
How's that for a start ??
I did that once to my ex-Filipino maid (the one before my current Indo maid), and she took less time shopping thereafter. But my mum is at home too, so I was not afraid of her for the sake of my son.
you are too loose on your maid at the start and I am afraid that there is too little you can do now. By the way, for how long will the contract finish, one year, 6 months .........
It all depends on the remaining period of contract and you have to assess the situation before you take appropriate means. Otherwise it is ineffective and to nobody's good.