How To Write A Claim Dispute Letter For Medical Bill . Dear sir/madam, i am writing to request an investigation of the following; The bill you gave me lists an mri scan for the cost of [$1,300. Dispute Letter for Debt Collection Assignment Point from www.assignmentpoint.com It should only contain the details of the claim request and the policy number. The bill you gave me lists an mri scan for the cost of [$1,300. The letter should be brief and to the point.