linq question - returning list

hi,
I have a method that returns a linq list.  it looks like this:
public List<listname> findCustomerData(string id,string name)
 { 
var customerList = ( from a in customers
                                 join b in orders on a.customerID equals b.customerID
                                where a.customerID = id
select new { customerid= a.customerID,datecreated= a.createDate,.... }).ToList();
return customerList; // error message points to this line.
I call this method like this:
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