When Arthur gets home after work, he receives a threatening text with a photo of Emily and a time-stamp of 7:29 pm. The threat implies that Emily will be killed in 12 hours unless ransom is paid. According to the phone screen, Arthur receives a text with ransom details at 9:13 pm, demanding the ransom by 1 pm, five and a half hours after the kidnapper(s) said Emily would be killed. As Arthur immediately begins collecting cash from his safe, Jane says they'll have trouble getting to the drop site by 1pm because it is lunch time. When Arthur walks down a hall while looking at the just-received demand text, a window with daylight is visible, so the intended time of day appears to be lunch time, still hours after the original deadline.
It would be close to impossible for any law firm to draft, finalize, and arrange formal service of a fraud complaint against a billionaire, plus schedule a deposition with him, all in less than one week. A demand for production of documents is usually needed first, with a minimum of two weeks for the plaintiff to respond, then a deposition is scheduled to obtain the plaintiff's testimony about the documents.
At about 36 minutes Doug tells Ben "Fruit of the poisonous tree. You taught me that". As lawyers, they would both have learned that basic rule of evidence in law school.
The end credits include a technical advisor to "Sir Hopkins". He should be an advisor to "Sir Anthony" or "Sir Anthony Hopkins."
The "fruit of the poisonous tree" doctrine applies only in criminal cases, where the police obtained evidence by violating the defendant's constitutional rights. The lawsuit in this movie is a civil action.