Always check your payroll statement carefully.
At the beginning of your employment relationship it is worth keeping an account of any evening, night or weekend work or overtime and any other out-of-the-ordinary working hours.
Contact your supervisor and ask for your pay to be corrected if you have been paid too much or too little.
If your employer refuses to correct an inaccurate payment, contact your shop steward or if your workplace does not have one, your nearest JHL regional office.