Unlimited Mifi?

A word of caution to those who want to access UK TV who do not have fixed line internet.
With the demise of BBC and ITV on satellite here I switched to ‘unlimited’ MIFI, this together with a VPN (fools the Beeb etc. into assuming I am in the UK) gave me back UK TV. This worked fine until my internet usage hit 15GB then the internet service almost stopped, dropping the speed from 10mbs to 0.1mbs.
I was told by the Mifi supplier that all providers do this. So ‘unlimited’ means 15GB per month. A strange definition!
Approximately one-and-a-half hours of TV equates to 1GB of download.
Richard Dew, by email