My gosh! This is absurd! Privacy information must be and shall be protected by the company (grab) because leaking a private information of a customer could lead to harm.
As for you miss @macchiata, you did the right thing to contact the help support right away. However, their response is not enough. Thus, it was very creepy to be texted and asked “can I get to know you?” Nah! Auto-blocked.
This has been an issue with other online services in the country. Grab/Shoppe food/ Maxim they do not randomize their customer number. Only Gojek that I know so far randomized their customer number so that the drivers can't contact the customer privately. Gojek learned from their customer complaints because some drivers can be creepy too.
Unfortunately, that wasn't the case with Grab where the driver and even restaurant owners have access to the customer number. I once was also messaged by a restaurant owner (via grab) asking me why I cancelled the order while it was actually the driver's request as he couldn't find the address. I lashed out and complained to customer service. Now, they improved the part where customers can chat directly to the customer without having to reach out customer's private number.
It was such a strange experience and I hope that driver won't randomly texting their customer like that especially without any consent.