Maybe It's Me

I had another altercation with a customer service person. We had to have termite treatments at our house before we could sell it...to the tune of $1200.
Back in September, I paid the bill in full but we keep receiving statements from Terminix. We've called and they tell us that everything is okay. So today, we received a nasty collection call. I called to tell them they need to update their records.
I started out very polite. Then "Sandy" got a little snippy with me. She said I sent the check to the wrong place and I should have sent it to them, not the corporate headquarters.
I said "Nevertheless, you cashed the check 2 months ago".
Then she started to scold me.

WAIT A MINUTE.

I'm the customer.

The customer who paid her bill in full 2 months ago. I said, "I don't care where I sent the check, you cashed it and there is a zero balance. Please take care of this."

Then she hung up on me.