Bookstore to stay away from

I have been buying books on Bobshops for more than 3 years now. And I sent the sellers messages about me paying latest end of the month. So this store have advised me that I must pay immediately. IE Bobshop allows 48 hours for payment to be made. So in the light of above - I made a purchase from them on 27 March and sent them a message that I will be paying within the prescribed period. I paid them the following day. And then - on 29 March they sent me a message that they don't have the book anymore. My response was that I am ok with that - but why did they not advise me that they don't have the book anymore when I sent them the message. Their response is arrogant and self centered as if they are bigger than the customer. So I gave them a bad review on bobshop due to their lack of communication and then they gave me a bad review - as a buyer. Even though I paid them within the 48 hour window. I have been buying books from more than 100 resellers but they leave me with a bad taste.