lost 20 dollars after upgrade

Hi I upgraded to the unlimited plan online without knowing I would lose my hotspot , so when I called to change it back to the 45 dollar plan they were nice enough to do it but would not refund my 20 dollars only had upgraded a hour or so earlier what a ripoff should be notified when something like that changes not wrote in the small print not happy at all service has been great up until this point gonna research some new phone company options