Well, you have your answer:
Take it back to that store
PS. take emphasis on the word 'should'. The person never said it 'will' fine, they said 'should' be fine. That means there is going to be an element of doubt as to whether they will actually accept it or not. Is bad though that none of the stores can give the same answer. All Apple stores should be operating under the same company procedures. If they are not then something is clearly wrong and not working because an Apple store is supposed to give the same answer when asked the same question. Apple corporate need to get a handle on this.