What would make Bangalore's marketplace groups actually useful?

I've noticed that when trying to sell something in Bangalore, people often end up posting the same item across multiple WhatsApp, Facebook and Reddit groups.

The problem is that listings disappear pretty quickly, and buyers may never see them.

For people who regularly buy/sell used items in Bangalore:

• What do you currently use?
• What's the biggest pain point?
• Do you repost the same item across multiple groups?
• What would make you switch to a different marketplace?

I'm trying to understand how people currently buy and sell used stuff in Bangalore, so I'd genuinely appreciate your experiences.

Are you building something?