Roofing and structural cost

[Prince Wilson]

I contacted two roofing contractors regarding a roof that have both shingles and structural damages. One of the Contractor ask me for the "Total Square Footage" of a building and give me a "Price Per Sq ft" charge without climbing the roof or seeing the property. They will supplies the materials but it is not included in their price. Still waiting to hear back from the other contractor.

Should I be worry about this contractor?

How can I figure out what the contractor total cost going to be?