Should I delete the mysql database user id created for my site by the developer? I am a newbie when it comes to anything related to databases. I cut ties with my developer who had set up my site and was hosting it too about six months ago. I moved my site to a new host thinking that that was the end of that.

I realised recently that he also had access to the database as he'd created a privileged user id originally(a user by his name kept showing up in my sql processes). Can he still access my database on my new host or is this user showing only because it is the only default user?

I asked my hosting company if this was a concern but they said it was not an issue. I have my doubts though. Can anyone please tell me how to educate myself about this and if this is a concern. I just want to learn enough to be able to run my content based wordpress site.

Recently my site experienced a brute force attack so I want to take all precautionary measures when it comes to security.

If this is a concern will simply deleting this user from the cpanel take care of things?
Please help
You can change the password in wordpress account as shown in 
Resetting_Your_Password

and change the cPanel user password also for secuirty concern.