Stock issues and customer care staff

I ordered a corner desk, dining room table and an office chair on the 4th of August 2020. The corner desk and dining room table was delivered on the 17th of August without the chair. I immediately phoned their customer care line upon delivery of these two items. They assured me that the chair is on its way. I phoned the customer care line again again this morning and the person who answered the phone informed me that Decofurn had not placed an order to receive more office chairs, she will inquire and phone me back before the end of day. I phoned again as I had not received any phone call from Decofurn or the person I spoke to this morning. A different person answered the phone this time and informed me that Decofurn will only be receiving stock in the middle of October. I then asked to be refunded as it was not acceptable to me - she said that she would send me the documentation to receive a refund (and that the payout would take 7 days after completion and sending the documents back to them). My question is, why offer products, take the customer's money, then not provide them feedback as to when stock will be ordered or received? I am insisting on a refund and will order somewhere else.