Brandi Glanville's Assistant -- FIRED After Dognapping

Brandi Glanville is blaming the whole stolen dog thing on her assistant -- TMZ has learned, the "Real Housewives" star has FIRED her right-hand woman for not taking better care of the pooch.

The 23-year-old ex-assistant -- who didn't want to be named -- tells TMZ, "I no longer work for Brandi. She texted me [Saturday] saying that I didn’t do my job by losing the dog."

As we reported, Brandi's Encino home was burglarized last Wednesday while she was in Palm Springs -- or so the assistant claims -- and someone made off with her beloved Chihuahua Chica.

After the alleged burglary, Brandi said she did NOT want to blame her assistant -- the last person to be with the dog before it vanished -- but something must have changed ... because the asst. tells us, that's exactly what Brandi did by giving her the chop.

Now the assistant's upset -- telling us she did everything in her power to make sure Chica was safe (double checking the doors, closing all windows, locking everything) and firing her just isn't fair.

Oh yeah, she also says Brandi still owes her for two weeks' work ... more than $1,000. Chica's still missing.

But Brandi's unmoved -- she believes the assistant made up the burglary story to cover the fact that she lost the dog. Brandi tells us, "I did what I had to do. If I can't trust her with my dogs, how can I trust her with my kids?" As for the unpaid wages ... Brandi says the check's in the mail.