Avoid at all cost

Booked a car through Rentalcars.com for a week at Faro airport. Paid online in the UK for 1 week hire and extra insurance, £137.00. On collecting the car, I was told what I paid was a deposit to the 'broker', and there were extra charges. After about 40 minutes trying to get to the bottom of what was happening (hot, tired, raining, cases and wife waiting outside office) I signed the paper and collected the car... after reading the hire papers on my return it transpires I'd bought "Super Top Cover', 'Personal Accident Cover', 'Tyre and Glass protection', and theyd changed my booking from me returning it full to them filling it for me (they charge for fuel and their time)
What I thought was a weeks hire for £137 added an extra £327 to the bill, deducted automatically from my Barclaycard, and as Id obviously signed this paper (stupid me) no one could help me. They are deceitful, purposely obstructive and liars. I cant believe that a company can do business like this. AVOID THEM LIKE THE PLAGUE