I don't think they were eliminated because of the van. The two other taxis later destroyed their chances, particularly the one that took them to a hotel and took their remaining money so they had to walk for hours to get to the next task.
But since the van ate up such a huge chunk of their money, they couldn't have taken another taxi if they wanted to from the hotel. The van was probably what led to their eventual downfall.
Except that they begged for money in another episode and got to the finish line, it was the final two taxi drivers who took them way off course and made getting to the finish before the others impossible. I hate that teams are forced to beg but in the past racers have managed to get money like that and survived, however if you are taken many miles off-course you are pretty much finished.
They really lucked out in that Vancouver leg. The people there are friendlier and are less adamant to give money to strangers. Even if the taxi driver took them to the wrong destination the first time, had they had enough money they could've just easily taken another taxi without having to walk for hours upon hours to the bridge. According to google maps, the walk from the hotel to the bridge was 4-5 hours.
From that point on, they already had no chance even if the 2nd taxi driver took them there successfully. Had they been more careful with their mode of transportation at the start of the leg, then the outcome for them would've been a lot more favourable and we would've likely had a different winner for TARAU2, considering how the cops started 2 hours behind the top 2 finishers in leg 11.