Is it legal for the employer to check employee’s personal phone?

As title.

Background: I work in a small private sector and we each have a sales target to reach. Recently, bosses has been on my ass for things that is not in the contract. They mentioned things like, have you follow up with clients? Why dont i have client retention? (which is false as data showed otherwise). Why did i not do this and that? (All NOT stated in the contract and wasn’t informed beforehand) and many more.

The story: I have 2 bosses and both did something that i was dumbfounded about.

Boss #1, “talked” to me about things that he was unhappy about (all of it was not stated in my contract). Then, boss told me to text a client to come in early so that i dont have to claim Time Off. I just said okay. And boss looked at me and asked what am i doing? Which bamboozled me. And replied, talking to you? Which boss responded to text client NOW and show it to him. So boss literally made sure i texted client to come in early if they can. Told me after that, next time if i have any clients coming in after work hours, tell them to come earlier so that i dont use many time offs (?????) And that i need to show boss proof that i text those clients moving forward to show that i am working (?????)

Boss #2, “talked” to me about similar things (note again that things they mentioned is not in my contract). Then boss demanded that i showed him my messages with clients to see if i did follow up. I’m like, no biggie right? So all my clients have their name saved as:

-Company name – Client – Actual name of client –

Showed boss in my whatsapp with all the client’s name while i was still holding my phone. Boss took my phone away and press back, revealing all my personal messages as well. I took away immediately and told boss that all clients in my phone is save with company’s name so its easier. Did the same thing, boss pressed back and read through my personal non-work related messages as well. I feel so fucking violated. Just for boss to tell me that, i did follow up with clients but ITS NOT ENOUGH.

Edit: just to add, i DID NOT consent of him taking my phone because i was holding it while scrolling all the client’s messages. He took it off my hand and went further away from me. When i saw he pressed back and look through my personal messages, i took it back immediately. Just for him to snatch my phone yet again. The personal messages he read through included conversations with my family members with sensitive topics. I tried taking my phone again the 2nd time but he blocked me instead, preventing me to take it back.

With that being said, is it even legal for boss to check employee’s personal phone???

Just to add, they are only doing this to me. They dont check on others. Which baffles me because my sales every month hits more than my other colleagues. I just had this conversation with 3 of my colleagues (lunch) and said that what they did is too much. Even worse, they dont micromanage them like how they did to me.