They only care for money and not the welfare of birds.
Many of the baby birds they have sold have sadly died.
They are rude, nasty and vindictive people, deal with them at your own risk.
If you still think they are ok, check them out for yourselves, ask to see the birds parents before you buy. See the breeding conditions, if they have nothing to hide there should be no problem. These are all checks that should be done before purchasing any bird, not matter where you buy from. Sadly Shop4Birds can't be this open, so maybe for this reason alone, it can help answer the question on what sort of company this is.