Don't underestimate old people, sometimes their driving dem ganas 
MT gear oil change so soon 

Don't bother. A lot, like magnet trap, engine flush, this flush that flush are pure optional rubbish.

They have no right to force you and they have no right to remove your warranty. The only possible issue is you bringing your own engine oil, but if it's branded and within specifications, there should be no problems. Unless they're about to publicly say that another branded engine oil broke your engine. Which would be a stupid thing to do.

You can check the front page for a service schedule with scheduled parts replacements, etc. Those are the only parts you should consider changing at the specified mileage. Even then, some people don't even bother to change some of the parts, like the belts, if the belts are still in good condition at the mileage point.