You are entitled to a replacement receiver at no cost if you have the Maintenance Plan, otherwise $20 to cover shipping and handling. This is the same for everyone. If on the other hand you wish to have a upgraded receiver or DVR to replace the receiver then there is a cost involved. Directv offers a "free" upgrade at time of contract renewal and in certain other cases, but many folks have to pay for the upgrade.
You are certainly welcome to post a rant, but the content of the rant makes it appear that Directv want's to charge you to fix the overheating while in actuality you requested an upgrade, correct?