Vodacom charges full amount for zero day usage of wifi

Took out a contract WiFi uncapped on the 30th of may recieved it on the 31st,got home sim was not working called on the 1st of June to get it sorted out.i look at my statement for June and see that my bill is remarkable high so I call the call centre to enquire only to find out Vodacom is charging me for the month of May for the WiFi uncapped for may.for what because I recieved the route on the 31st.this is daylight roberry.i have been with Vodacom for almost 10 years this is super disappointing