World No 35 Pella and world No 93 Hugo Dellien were both withdrawn from the event and sent to quarantine after their fitness trainer, Juan Manuel Galvan, had tested positive.
The move was widely criticised by players - including president of the ATP Players Council Novak Djokovic - as neither Pella nor Dellien had tested positive since Galvan's result.
Australian Open
'I felt ashamed' - Osaka opens up on mental health battle
With the tournament under way, Pella has now released a statement on Instagram to express his annoyance and reveal Galvan has tested negative for the virus.
“We had no information from the tournament or the ATP. I gave my fifth negative result of Covid-19, as did Hugo and Jose (Acasuso, their coach) and nobody tells us anything.
And yesterday afternoon they tested it again on my physical trainer and he was negative. Imagine the feeling I have.
"I don't know what will happen at the time, who will take charge and what solution they will give us from the tournament. Juan is negative and apparently never had the virus."
Unless the decision is changed, Pella and Dellien will miss the US Open, which starts on August 29.
"I do not know what will happen,” added Pella.
“But here there was a very serious error on the part of someone. I hope they can give me pertinent explanations, because what I went through this week was very difficult.”
'I owe him a lot' - Wawrinka grateful for Federer's 'help and support'
Australian Open
Alcaraz's coach not expecting another huge physical off-season transformation