Refueling charges are bogus

I hired a car from Tempest twice in a 3 month period.

Each time I hire a car they suspiciously need to refuel it. They charge you an amount for fuel which is **** and then a levy to refuel on top of that. I think this is a little more than a strange coincidence now and more like common business practice! The last time I was told they are investigating this. Unsurprisingly I never recevied feedback. I'm sure it's not only them who do it; but they just got caught out now.