Pricing error and No communication

Good day i would like to complain about my order number ***5 i purchased a few items including a heater and only to find out that they said there is an error in pricing after have already paid and i was made aware of that after seeing that my delivery stuff is missing and no one bothered to inform me that there was a error pricing for the heater and they just credited the store credit without my authority, after i called that was when i was informed about the error