Beware of Scammers on OLX

Had an interesting experience today as I have listed an item for sale on Olx.in. This is what happened and I'm narrating it since many of us use it to buy or sell pre-owned items in India.

Scammer calls from a number which truecaller already shows reported as spam.
Speaks only Hindi (I caught the accent to be Rajasthani), asks about the item, informs me that he found it in perfect condition as per pics and details and is inquiring for his friend who lives in Mangalore.
Tells me his friend will pick it up tomorrow but he wants to pay for it after we agree on a price.
Takes my UPI id for making a quick payment and hangs up as I inform him I text it to him.

At this point I already told him that I prefer his friend comes over checks the item, make payment and take it. He assures me the items from the pics looked great (which they are actually) and he'll make the payment now as he want's me to hold it for him.

He calls back again and tell me he's sent me a msg for Rs. 20000 (we had agreed to Rs.22000) and I need to accept it via UPI. I felt it might be an advance or he's low balling by sending a smaller than agreed sum and force me to accept it. In any case I simply said I will check if I have received payment which I hadn't at the time.
At this point he said he's yet to send, he's just sent a msg for this amount and asks me if i have received it and accept it if I get it in the UPI app. He said he uses a PhonePe merchant app.
I hang up (suspecting some foul play) after telling him I don't have PhonePe UPI app and will need to install it and will call him back.
The second I hang up I get an sms from my bank saying there's a "collect request" for Rs. 20000 and I need to login to my app to approve it.
Collect request implies that someone wants you to accept their request for money. If you accept and make payment you will be sending this money to them.

It was a clear case of fraud as you can tell. He was asking me to accept his payment request while if he was a real buyer, he would have simply made the payment to my account as he has my UPI id. Nothing else was needed. Many gullible people in their rush to receive payments actually end up making the payments themselves and get scammed out of their money.

I don't generally accept calls from unknown numbers but OLX buyers never have the courtesy or decency to text and then initiate a call after receiving a response. Even if you request them over DM to do this they still call you at odd hours and that's why I picked up knowing it's futile to tell people over marketplace like OLX and I also wanted to sell my items quickly.

He called again but I didn't answer and simply asked him to text me. There was no text (not that I was expecting a real response back). I also reported his account for fraud to OLX.in and left it at that. Because there's not a lot more I can do in this case.

A real buyer would've called me himself, setup a time and place for meeting, checked the items, paid for it, collected it and left. If it were online, speak over the phone, agree to price and terms of delivery, make payment and then accept delivery.

If I get a call again tomorrow I'm just going hurl a ton of abuses now or simply have some fun.

But moral of the story is, don't be in a rush when selling something online on any marketplace website. Take time to consider the offer you are getting. There is no dearth of scammers, time wasters, low ballers online, not just on OLX.