TOMSWomen's Classic Espadrille Wedge Sandal

I got mine and love them but my heel keeps popping out. So tried inserts and still keeps doing it. How do i fix it? If go down a size are to tight

How high is the heel?

Can anyone who has bought them can tell me if the foot slide all the way to the toes where the toes slide out too much? I have had such issues w/style

I have weak ankle, are bottoms spongy or solid?