Rest assure that it is not us. I had a live chat with 2CO and I will post below to people know what is happening.
QUOTE:
Please wait for a site operator to respond.
Chat InformationYou are now chatting with 'Gena'
Gena: Hello. Thank you for contacting 2Checkout.com. How may I help you?
you: Gena hi I am trying to make payment and I am getting this error Parameter Error.
Gena: I apologize for any inconvenience that this may have caused you, but we are not accepting orders from that website at this time.
you: ohhhh ok thank you
Gena: You're welcome.
SO it seems TemplatePlazza is dead?