Night Surfer Data

<p>Why is it that my night surfer expires on the 20th?</p> <p> </p> <p>Should it not expire on the same day as my normal data ie on the 31st of May?</p> <p> </p> <p>As you can see below it expires on the 20th</p> <p> </p> <p>Bundle Expiry Date Available<br />Campaign Free Telkom Mobile Night Surfer Data Fri May ***5 MB<br />Included Telkom Mobile Data Tue May ***3 MB</p> <p> </p> <p>This is on the Home Office LTE 50 GB</p>