Sorry to hear this, and I do have some sympathy with TG, but you're the customer, you've paid them for a service, and you've got a broken item. I'd fire in without a moment's hesitation.
Ignore whatever you've been saying directly to TG. Open a fresh PayPal dispute and just say that the item is completely non functional. Nothing else, no background, no "I used it for a bit and then it broke."
If TG want to dump the history of your conversation in there, that's up to them, but you just stick to "Non functional, refund please."
If PayPal don't resolve that in your favour, then you go on and do exactly the same thing with your credit or debit card issuer, and tell them to issue a chargeback against PayPal. Same process, just "non functional, seller refuses to fix."
Best of luck, and hopefully it will be a simple fix. Worst case, you should be able to bin off the magic parts and just rewire it for a standard trigger, but then you're losing out on what you paid for.