After reading through the whole thread, I gotta say that I'm amazed with the experiences you've all had with these 'slimming' companies. My gosh!! For 5k, you can pay for gym memberships at SEVERAL gyms, and with the spare change, still purchase their personal training service. Or you can also hire the services of a personal trainer whose job is to educate you on what to do, and best of all, you can check to see if the trainer is certified.
It's really easy to promise you the earth to get you to sign on, but after the money goes to paying their wages, they're not bothered abt you anymore. Neither will they care if you come back cos as far as they're concerned, they have more waiting outside to sign up.
Regarding the restricting of diet to 1000 calories a day, that's a real good joke they told you, cos when you starve yourself like that, of cos you'll lose 'weight'. Your body needs about 1500 calories a day to sustain your basic survival, so by putting yourself at 1000 calories a day, what will happen is your body will (a) store the food you eat as fats to use in times of starvation cos as far as it's concerned, you ARE starving and (b) your muscles will 'waste' away cos your body will break down your muscles for food cos they're no other sources. And when you lose muscles, you lose weight too. But it'll mean you'll have no strength (literally) for anything then.
As always, the best way to lose fat is through a sensible diet AND an active lifestyle. In order to lose fat, you need to spend more calories than you eat. Simple as that.
I'll be more than happy to answer your questions if you have any. FYI, I'm a qualified health and fitness professional, so I DO know what I'm talking about.