lack of communication and overbilling

We wanted to use one of our business SIM cards in a router for data and asked for a recurring 5gb data bundle to be added to it (it previously had little or no data). We got an email from \dealer assist"in reply to our request saying \""Your 5 gig is activated\"" on the 22nd of October so we put it into a router and started using it. Then in the beginning of November another one of our business SIMs got an sms saying there were unusually high costs we should investigate. Long story short it turns out the 5 gig recurring data bundle only kicks in at the beginning of the next month"