I should contact the supplier,
it's not normal frogs dying on you in such short notice.
Maybe you can arrange something with them.

I must say at first glance, nothings wrong with the frogs.
They seem well fed to me.
It would be guessing what happened.

Can you make a picture of the enclosure and say what the humidity and temperature are?
Maybe there is room for improvement or something.

One thing i would like to comment is,
you can better use a bowl of stone or plastic instead of a steel one.
There is a possibility this puts in metals (not sure of the English word) into the water
wich is not healthy for the frogs actually.


Anyways, contact the person who sold them and tell them how quick they died.
A healthy frog shouldn't have died that easy, 2 of them is even more doubtfull.