post couriers do have a policy of not shipping animals but some branches allow it.
Your experience is common as said until they get to know you,
There is no insurance for shipping fish, It pays to write on the box LIVE FISH, The last time I shipped I forgot to do it and yes that's right it took 2 days to arrive luckily it wasn't a frost and they survived.
there was a topic not so long a go that mentioned many company's that will ship fish, try a search.
Have read the sticky at the top of this forum on posting fish??, there are many hints and tips their.