Charging for shipping seems to be common in todays parts world. I went to my Ferris dealer (also sells Mahindra ) for a deck belt for my mower. He didn't have any, nor did a dealer 30 miles away. Seems rather stupid for a dealer who sells 2-3 brands of mowers not to have a common wear item in stock. It is really common for me, have to replace it every year so far due to breakage about every 50 hours. I have a Craftsman ZTR that is 5years old and only replaced belt once when I got some trash under the deck, belt jumped off and cut it in the process.
Back to the issue, IMO, dealers should stock all common service items for all models that they sell. I always buy at least one each of the 50 hour service items when I buy the tractor. As a note, I would not stop using the tractor if dealer has no service items. Just get them changed ASAP when the filters come in.
I would also be looking at a OEM replacement from NAPA or other supplier.