I have a ST-901W with some issues.
The devide is working well, the SIM is working well, but:
Can anyone help me with that?
That's how it's supposed to work. If you need it to have a diferent way, you must configure it for it.
You will learn a lot if you start reading the manufacturer's manual.
I have bought a ST-901(ST-901W 3G/4G) from local market in Sri Lanka.
It's not allowed to change my password. When I tried to do it "Sorry authority is limited".
Also it shows my profile as a "Group user".
It shows local seller's name as the "provider" in Sinotrack Pro application.
Can you please help me to clarify this thing.
That's something you need to clarify with your device's vendor and/or by reading device's manual.
You may have bought a used device, or factory locked.