Wrong amount invoiced after upgrade

Hi,

Can you please explain the extra R41 thats been added to my account for this month. This show on my latest invoice that was emailed to me.

I have been paying R1199 per month for my 50mbps line. The upgrade I requested 2 weeks ago was to 100mbps for the exact same amount R1199

Nothing should have changed on my debit order.

I expect very urgent and immediate reaction to this.