My thoughts exactly!
Why the hell are they interviewing you, when you'll be the one handing over the big $$$. You should be interviewing THEM to make sure they are going to provide you with a level of service that you desire.
And NEVER EVER EVER PAY UP FRONT FOR ANYTHING FLYING RELATED. Only pay for it once you've received it (I.e lessons, only pay for them once you've finished the flight).