Sorry but i don't understand what you mean by having a companion pet and the thing i want to say about my experience with this glitch is when i had 3 pets and i was meant to receive 2 pets for my big pet but i only had one space therefore the trade couldn't be done therefore we made a deal ( me and the trader ) that he will give me the second pet in a separate trade as we couldn't do it in the same trade.
For more info and proof, i have posted that scam on report/ player abuse under "SCAMMED
I HAVE PROOF can you please tell me if it was my fault or what i should do.