Edit: sorry the photos are hard to read. just realised they assert you have not paid your 70% this will put you in a different situation from me. You need to really focus your argument on the Consumer/Business debate. This is what they are relying on. you may need an accountant to show you are not reliant on this product as your main source of income, i.e. you have a job or another business.
I don't think not paying the 70% is particularly relevant with regard to the 8-10 week shipping date. The fact that Alpha REQUESTED it is the key. They say in their T&Cs balances will be collected 8-10 weeks before the SHIPPING DATE. Not, "Your item will be shipped 8-10 weeks after receiving full payment". This may seem small but it implies that those that paid 10 weeks ago should have their item and those that pay today will get it 8-10 weeks from now. This is clearly not the case.
Alpha were supposed to ship 8-10 weeks after they requested final payment that is why they repeatedly said the 31st of July would be the worst case shipping date. Exactly 10 weeks from the final payment demand.
Also the lack of Paypal/CC payment options removed the ability of many customers to pay. They also said the EXACT SHIPPING DATE was to be provided when payment was requested This was not the case. All of these are breaches of contract no matter how Alpha slice it. If they are going to argue this case based on their T&Cs I think they are in big trouble.