Hi I think you need to have a good read of the faq's around how the reservations work as what you have described is not possible unless there is a glitch,
log on and update your calendar to block out any dates you don't want to rent, people will then send you reservation requests which you need to accept or decline. They cannot send you requests for dates unavailable on your calendar. If you have instant book (if you do I recommend you turn it off until you are more familiar) then they can book without you approving but again, only on available dates in your calendar.
I have texts enabled but they say 'Jo wants to say 20 dec for £xx reply accept ....
when end you get a text just go on the app or website and you can then look at your guests profile or message then for info if you want to. You then decline them or accept them.
Guests can still send enquiries for unavailable dates (I think) but they cannot book them