No support & mention of recurring fee

The response was quick enough when I was looking to buy, but when I tried to install the paid plugin it came up with fatal error. Followed the directions for if this happens from the website but still no luck. Stuck with a plug in that doesn’t work and no answer after four days from customer support. I guess it’s down to me to try to figure out what’s wrong, if at all possible. Disappointed. Also I noticed that on a payment email it said recurring fee, now concerned that I’m going to get recharged for this. ??