According to a statement sent by ZOL confirming the price increase.
"This serves to notify you of a 15% price adjustment on specific Wibroniks packages. The adjustment is effective 16 August 2019."
"All unpaid Unlimited Wibroniks subscriptions will be charged at the new price starting 16 August 2019. Payments made prior to the 16th of August will be deemed as settled for the month of August and will not require any top-ups. All prices for Fibroniks packages remain unchanged." ZOL added
Below are the prices: