UPDATE
I just called them and here's the conversation:
JL, "Hi, You guys cashed two of my cheques a while ago andsaid you would refund me a cheque two weeks ago."
.
..
...
UVic, "Okay, I don't know why but we've never sent a cheque to you."

Me =

JL, "Alright, so what now."

UVic, "I guess I can send you the cheque."

JL, "Please do that ASAP, maybe even today."

UVic, "OKAY! BYEBYE."

JL =

Thanks Kendrick, for reminding me.

 

You should get the person's name, so the next time you can hold that person responsible for his/her "OKAY! Byebye (I'll send you the cheque today)"

 

A little too late for that this time.
But thanks for the suggestion.