Why are there deadlines for replying to Retrieval Requests and Chargebacks?

The card schemes set stringent time restraints on all Retrievals andChargebacks. We usually give our merchants 14 days to reply to our letters or faxes. If we do not receive a reply to a retrieval request within the specified time limits, this can result in a Chargeback for not replying, that cannot be remedied at a later date.