When Gemma and Tom are leaving in their silver VW, the car is shown with alloy wheels. During a close-up a moment later, the alloys have switched to plastic hubcaps, and then back to alloys.
When Gemma and Tom are trying to leave the strange neighborhood with the car, Gemma looks at both cellphones. Neither one shows a phone network. But they could have used GPS instead, to find out where they are, and find a possible way out. Except that there is no reason to suppose that GPS would ever work, in an alien realm where space and time are distorted, and the ground itself can be bent and twisted.
When the main characters are dancing in front of the car you can see a crew member hiding behind the car door.