What should you do when someone else is accessing WhatsApp using my mobile number

SOLUTION 1

First of all take another mobile and sign in what's account as same number

Then recovery all data in ur new mobile when recovered ur data then ur old what's app account is automatically closed bcoz ur start what's app as same no. In another mobile so ur old mobile what's app account will be closed in one second

If the another mobile was not yours and if u open what's app as same no. In friends mobile and make shor that after ur work is done take a second go to settings and clear ur all what's app data in that mobile now no buddy used ur what's app

SOLUTION 2

If your SIM card is active then simply install and setup WhatsApp account on any other device and this will log your WhatsApp out from other device automatically.

1. If your SIM card is deactivated and number is alloted to someone else then you can't login with the same account that easily, here you have following options.
2. If it's prepaid then Get the SIM from the other person transferred to your name. It won't work that easily though and entirely depends on other person.
3. If it's postpaid then mobile company can help revive the SIM for you again with the same number.
4. Login to WhatsApp with old SIM number. Change your WhatsApp number under settings to a new number you have. You'll need the help from new owner of your old SIM in entering the OTP for verification process though but it is a one time affair.

SOLUTION 3

Since you’re using a basic phone, borrow a smart phone from someone and follow these steps:

1. Install WhatsApp on their phone if it isn't already installed, if it is already installed ask them if they are okay with removing it and reinstalling it again. If yes, continue, if not search for another person.
2. Now go on and create your WhatsApp profile. In the process it will ask for your phone number, it will send a code to your phone which you’ll have to enter into WhatsApp to login.
3. If your number is being used by someone, once you enter the code, it will automatically fill up the ‘Name’ field with the name of the person who is currently using it. If it is blank, enter your name and create your profile.
4. Now you know the name of the person who’s using it or you don’t, either way you now have control over your WhatsApp account, because once you login only one copy of a profile can exist, hence the previous one will longer be there and the person who was using it will be logged out automatically.
5. Now go ahead to the settings and delete your account.
6. And now you don’t have a WhatsApp account linked to your phone number. Next uninstall WhatsApp.

Every time you want to login or create a WhatsApp accounnt, it will send a code to your registered phone number, only if you type in that code in WhatsApp you will have access. Without this feature a solution to your problem might not have existed.