[Jay]

On Aug 7, six persons of my family were planning to take a group tour that we would join the Salt Lake City Airport to other group members. But unilateral cancellation of my flight due to crew problem causes my family miss the group that we had to join in the airport.
To compensate our tour for Salt Lake City we lost, I asked Delta airline customer service in IAH airport of Houston to rent a car on Aug 11 (I had had to waste one day of our vocation to compensate the lost day in Salt lake city.). Customer service in Houston told me to request the reimbursement after use of car rental after communication with other (maybe supervisor) using phone. When I come back to wait the next airplane and searched expense for rent-a-car, it was too expensive because of high demand season.So I asked again using call number for customer service whether I could rent a car or not.The responder on line permitted me to use a rent-a-car after discussion with someone (I had waited for a while holding the phone).
In summary, both Delta Airline Customer Service in Houston and call customer care service told me that after I used a rent a car first with my expense and then would request to reimburse the expense using fax or mail to Delta Airline Customer Care, they would reimburse my expense to me. So according to direction of Delta Airlines, I did like that. After arriving in Houston, I had sent my ticket information and rent a car receipt using the fax No. 888-286-3163 (They informed me this number kindly).
However, after a long time a coordinator working at customer care of headquarter sent me email that Delta Airline could not give reimbursement to me. There was no fault to me. I only followed their staff's direction. If they told me that I was not able to rent a car, why I use it with much expense!!
That is not my fault, so I can't endure my damage.
Why do they tell me differently in same company?

Investigate and confirm whether an employee working at customer service in Houston told me or not.
Why am I damaged without reasonable cause?
Why are alpha and omega different!!!!