I feel there is no such thing as a good maid agency. Personally, if one gets a bad maid (unless the agency really screens the maid which is really unlikely and almost impossible for fresh maids), either have to live with her or keep praying the next one is good. With all the MOM rules and all the princess maids nowadays, I rather worked like a cow then keep paying their salary, the things they broke, pay for maid utilities and food and get lousy work from them. This is after I tolerated a bad maid for 1 year plus. The financial stress(she broke and damage so many things and I have to keep buying) and most, the mental stress (keep wondering what else she can cause damage to kids and house and always have to pre empt her behaviour, eg draw curtains for no reason but leave the house forgetting to close window, small thing but if it rains, I will probably have to replace whole parquet floor which by the way already is rain sod marks because it is so hard for her to close the windows).
If the maid is bad, the most they can do to help is process your refund quickly, since insurance is processed by insurance company, no difference and supply a new maid quickly but honestly, if they do not have good maids, you end up waiting forever also since this depends very much on supply.
Of course, agencies like universal sg which really seems terrible from the start, are the ones everyone should really avoid.
When I look for agencies, after so many tries, I realise the ones that are really fierce and will question maids are those that are slightly better necause they have alrrady put some fear into the maids. I do not like to control by fear, but I realise in my experience, if the maids do not have a little fear or mainly respect or just think one is soft hearted, they will give you trouble.
The other thing to consider is this, I always tell my maids, there ,frequent bad work (knowing how to do but dont do)doesnt entitle return to agenc and I will always tell them, if anything happens to my kids, i will not hesitate to put the law on them until they get punishment