While I do understand that there might be some complexity involved when dealing with payment gateways etc, 6 months sounds too long.. were you learning development on the way ? I'm honestly curious...
Additionally both myself and my partner have learnt a lot along the way, for instance we now have one designer we can rely on to get the job well done and on time. Our previous one disappeared for a month on holiday without warning and I admit, we waited too long before deciding to move on and find a new designer. Little niggles such as this slowly but surely kept pushing back our deadline.
We've had users persistently asking us when are we going to launch so you're not the first, nor the last. Thanks for your interest however :)