After you get the first profit from your "job" with them, stop replying.

These fellas want you to buy stuff, then they will give a commission.

BUT
Only the first payout is genuine.

Then you will be asked to buy even more expensive stuff ... but will never get compensated for it.

Get a contract in writing before you deal with these people. "Jobs-by-WhatsApp" is an easy way to get scammed.