yes
can a employer contact you while you are covered by a sick note
Certainly.
EEOC -- Employer Equal Opportunity Commission
Contact your employer, they can change it for you. You most likely will need to contact the person who is in charge of payroll, as was the case w/my employer.
Contact your employer for a replacement.
What the purpose?
No
If your reference has a prior relationship with the potential employer then the contact would make sense. If not, no.
you should contact your employer
They should have been mailed to you by your employer. Contact them.
If you have not informed your present employer that you are searching for other employment, you might want to request that potential employers not contact them. If that is the case, make sure you have strong references and former employees that they can contact.
Yes, if it is determined that your employer is not taking enough tax from your check to meet the minimal requirements.