Unable to View Contacts:
It is likely that you have a restriction on your user profile whereby you can only see the Dashboard and History activity that is linked to your own user profile and not for any other users of your CRM account.
You may also have a tag restriction in place - meaning that you can only see contacts with a tag applied that you have been given access to.
For any changes to your security access to be made we need the authority from the Key Account Holder who will need to contact our Support Desk to request any changes.
Unable to View History:
A reason you may not be able to see a contacts History is if a contact has previously been marked as SPAM and then restored as a contact record - when you mark a contact as spam it deletes the history from the contacts record.
Please contact our Support Desk so that we can restore any history associated to a contact that was once marked as spam.