I've never bought coins with Paypal, but have had an account frozen a few years back for no good reason - living outside of the USA, they somehow thought my account was "suspicious" and froze it. Lost around $140. Paypal is a necessary evil for a lot of online transactions right now.... but I wouldn't tempt them by doing something in a gray area, as their policies are fairly arbitrary, and since they're not a bank, there's not a lot you can do if they decide they want to just take... I mean freeze... your account.
They normally ask for Identification when freezing a account and require evidence to who you say you are. They normally sort it within 48 hours. You should of contacted them and sorted it. I'm not sure if you can still contact them and get it back.
They normally freeze accounts for suspicious activities or for people reporting you. (Happens often with ebay if you search the internet).
I had those kinda issues years ago when my sales volume started to go up. Gave them what they wanted and have never had an issue since.
They have done some cool things in the last few years. Like letting me send money for free and have made some favorable comments in reference to bitcoin.
I dont love them but they are alright.