Did you ask for a confirmation email of the increased fee? saying in your
email,
if you are sending me a confirming email of the increas fee to $12 I will do the shop. If you dont send the confirmation email naming the increased fee due me, , do not assign the shop to me."
simple.
Yes, it happens often with that company.
Fortunately you are only out $5.
Some people have been promised much more and never receive it.
You have to consider if you want to continue working for a company that does
not keep its payment agreements.