Amazon returns - ticket

Just wanted to know why does amazon customer support raise a ticket on asking for return of some items. I have many times avoided writing to amazon in past if sometimes I receive some items with minor issues, but when I order on amazon fresh and after delivery realised that some of items have issues regarding expiry of some items which has just one day left to expire and replace them they said they have escalated the issue and have issued me a ticket number.

I have earlier too raised issues with amazon but my returns have been very less and they have been good to issue refund, today I was surprised when I wrote to them they sent me some ticket number and not resolved the issue at onset.

Please advise what does giving ticket number mean and to whom they escalating the issue with as amazon itself is the seller and not any third party vendor.