Do you use RedHat Linux ? If you do then think of Plesk support as working on the same sort of model.
You buy the software, but you then have a choice of support options. You either pay for no support at £0.00. Or you pay for email support. or you pay for phone support. The option is yours. In this way, those who don't require support don't have to pay for it. those who occasionally need support (like me) pay a little for it. and those who need a lot of support, pay a bit more.
Alternatively, you'll find plenty of help with all sorts of things on these forums. I could not do without them. I've learned so much from some very helpful people.
You do not have to pay for reporting bugs. You can send bugreports to (I think)
bugreport@plesk.com (or is is @sw-soft.com?).
And within your first year of purchasing plesk, you are entitled to free software updates. after that you must pay for an update contract (SUS), or pay an upgrade fee.
All this assumes you purchased your software from sw-soft directly. If you purchased from a dealer then they may have different policies.
All this is perfectly reasonable, perfectly normal and similar to the policies used by many other software vendors.
Sure, I'd prefer everything to be free in a way. But I chose Plesk over the totally free alternatives for good reasons, and as a result I have to pay for certain things, which to my mind is perfectly reasonable.
Faris.