The Blues claimed the decisive second goal from the penalty spot after Raheem Sterling’s first-half opener squared up the tie, with Dortmund winning the first leg 1-0.
The penalty itself was tough, with Ben Chilwell’s cross striking Marius Wolf’s hand albeit without much opportunity to adjust and with his arm by his side.
Either way, the spotkick was awarded by referee Danny Makkelie upon consultation with the VAR but re-taken due to encroachment after Kai Havertz had spurned his initial attempt into the post.
There were Dortmund players encroaching inside the box but they were alongside chasing a Chelsea player also encroaching.
“I’m not sure what more he can do with his hand,” Bellingham said on the penalty award.
“That in itself was disappointing and the fact that they’ve had a retake, I think it’s a joke.
“For every penalty, especially when you have such a slow run-up, there’s going to be people encroaching into the box by a yard or so.
“He’s made the decision and we have to live with it.”
Bellingham wouldn’t be drawn further on the decision, fearing financial sanction.
“I don’t want to get in trouble. I’ve paid enough to them lot,” he said.
Dortmund boss Edin Terzic declined to focus on the VAR, who aided Makkelie’s decision.
“If a decision takes about five or six minutes then it’s not easy to make a call,” Terzic said.
“But as the manager of the team, I’m responsible for the performance of the team and staff, but not the performance of the referee.
“We didn’t speak about the referee a lot last week and we won’t start with that tonight.”