Please also note: You will need to view your contacts in 'person' mode and not in 'organisation' mode to be able to bulk delete contacts in List View.
The screenshot below shows contacts displayed in List View:
To view your contacts in People mode click on the person icon as shown below:
To change your view to people mode please click on the 'person' icon as shown in the screenshot above.
You will then see the Delete button as shown in the screenshot below:
If after doing this the contacts are still not deleted then this is likely to be a security setting. Please check the Security settings on each contact record you want to delete. It is likely that a restriction has been put on which allows you to have only read-only access.
To find this please click on the Edit button inside the contact's record as shown below in red:
Here you will see a Security tab:
If you have read-only access you will see that in the column heading Permitted users/groups that an R with a check in the box will be beside your name as shown above.
Please note that only the Key Account Holder or Admin Users can access the Security tab. If you are a Basic user you will not be able to see this tab.
Please firstly check with the Key Account Holder as there may be a reason why you cannot delete this contact.