FlyInfinite Worst company, Stole my money Burlingame California

This is the worst company I have ever dealt with. I booked a flight to Thailand with them in July, flying with my daughter who is under two. Yuri quoted me a price for an adult seat, and told me that he would waive the child fee. When I came to book he backtracked, telling me there was no way he could waive this fee. The price that he had quoted me had now increased considerably. After some deliberation I agreed to book the flight, and he sent me an e-form to sign with the agreed price on it. After signing and returning the form, my bank informed me that a sum of money- considerably higher than the flight price- had been charged to my account. I contacted Yuri and he told me that tax charge had increased, so he had booked it and charged me several hundred dollars more than the amount I had signed. I was absolutely astounded as this is not only bad practice, but completely illegal. Yuri literally pleaded with me to agree to the new amount, offering to 'pay half' as it was his mistake. I could not see why I should pay any amount more than what I agreed if he had made such an error and misused my card details in this way. He then begged me to agree so that he 'didn't get in trouble with his boss'. Shocked by the way he was talking to me, at this point I was doubtful that I was even speaking to a legitimate company. I requested a manager, who apologised and said that he would half the amount that I had been overcharged, and give me a gift voucher for the amount that I had already been forced to pay unknowingly. Such incompetence, followed by poor customer service, left a very bad taste in the mouth. Anyway, they sent me a corrected booking e-form which I really had no choice but to sign as the amount had already been taken from me.
A month or so later, a work issue meant that I could no longer fly to Thailand on these dates. I contacted Yuri to cancel the flight, and after several unanswered emails, I called Fly Infinite only to find that he did not work for them anymore. I believed he must have been sacked over his terrible misjudgments; however I leaned that behaving unprofessionally and misleading customers is characteristic of Fly Infinite and ignored by their management. I was handed to Dan in order to cancel my flight, and my experience went from bad to shocking. Firstly he informed me that I couldn't receive a refund. The e-form I signed (AFTER my flight had been booked by Yuri and money had been taken without consent) states in small print that my flight is non-refundable. Why had I never been told this? My only option now was to pay a £675 cancellation fee and then I would receive the value of the flight as 'store credit'. It is ridiculous to pay this much money to cancel a flight if there is no refund after. I've never heard of a company forcing this, in many years of travel. Eventually I called Dan and agreed to pay the amount, as long as it was still the same as he had quoted me. He told me he would take my card details, then email me the cost and cancellation e-forms. He assured me that nothing would be charge to my account until I had confirmed the amount and signed the forms. Dan then called to say that money would come off my card, but not to worry as it would go straight back on: this was 'part of the cancellation process'. I told him I was extremely confused, and he hung up. How could he cancel my flight if I had not confirmed the cost OR returned the forms?! My bank then told me £1117 had been taken by Fly Infinite. They asked if I had authorised this charge and I had to say NO. A fraud team blocked my account, but they could not stop the payment. With my card blocked also, I could not even buy food the next day. The amount was £500 more than what I had in my account, so every day since then I have also been receiving overdraft charges. When I contacted Dan admitted he had overcharged me for the cancellation fee, and that it was not what we had previously agreed. He wasn't troubled that he had used my card illegally or cancelled my flight without my consent. When I explained the inconvenience, financial costs and stress this had caused he issued me 2 gift vouchers for $500. Like the gift voucher given to me by Yuri these are only to be used on separate 1st Class seats. 
Therefore in order to actually receive any compensation, I would have to book 4 1st Class travel seats. I have to spend thousands of dollars with Fly Infinite if I wish to benefit from their 'gift'. 
Their actions and attitude are disgusting. I have complained to the company but-despite the serious nature of illegally using my card details TWICE, and the financial costs that I have wrongly incurred- my complaint is not being dealt with. Unless I am refunded for my initial flight AND cancellation I will be taking legal action against Infinity Travel Group.