She went on to say that her and her sister Jessica were signed up for the show "under the guise of charity and heart".
"Our genuine intentions and passion reduced to an edit – portraying us strong-arming other team members and outwardly using our mother’s condition for sympathy and manipulative tactics is disgusting," Lisa said.
"And it was you who constantly asked us to reiterate our charity and why we were there during this episode and you turn around and weaponised our words and our mummy’s name – turning them into a knife used to stab us in the heart. Shame on you," the 36-year-old wrote.
Lisa went on to write that what the show has done to them is "gut wrenching, soul destroying and the lowest thing" they could do to them.
"You have used us at the most fragile time in our lives. This was never a game to us, this is our reality we were fighting for," Lisa wrote.
"Hoping to turn out pain into something positive. Things doing get better from here for us. So you win. I hope it was worth it."
It comes after Tuesday night's episode of Celebrity Apprentice aired, where it focused on The Veronicas as they took on the roles of project managers.
The two were fighting to win so that they could raise money for their chosen charity, The Brain Foundation, in honour of their mum who is suffering from a rare neurological condition.
"We want to raise as much money for our mum's charity as possible, and this is the biggest chance we have," they explained in the episode.
Their desperation to win saw them clash with a number of their co-stars on the show, which led to viewers criticising their behaviour.
Many took to Twitter to voice their opinions, with one user writing: "I get their Mother is sick, but using her as an excuse throughout this entire challenge is pretty poor.
Everyone is there for their respective charities and the Veronicas are acting as if their charity is the only that exists."
"Goodness gracious, the Veronicas guilt tripping everyone," another added.
A third user wrote: "The Veronicas hearts are in the right place, however their open mouths are raging ahead of any logical thought ..."