Ok, there are two types of contact, a Request to Book which you have to accept or decline within 24hiurs or and an Enquiry, you have confirmed you received the latter.
With an Enquiry, as you have mentioned, it is just a question and does not mean the guests wish to book or will book once you have responded although you are required to make the initial response within 24hours to avoid your response rate being impacted. You do not need to send any special offers for an Enquiry or even a Request to Book; any special offers are strictly subject to your decision to offer such. You do not need to provide quotes either as this is automatically provided by Airbnb when the guest does a search and finds your property.
It is not clear how you have been penalised and why you feel any penalties are as a result of this enquiry you received – perhaps you could clarify this in order to receive a more specific answer?
BW, Ama