Missing box

It has come to me having to write on Hello Peter because your consultants are ignoring my mails and I have been calling in to solve my query since the 4th of June. I ordered a wall unit and received 2 boxes of the background but one box of slates is missing so out of 3 boxes 2 were similar and one part of the wall unit is missing, I stated my query and asked for a collection of the duplicate and a delivery for the other part so that we can complete installation, we have already began the process so other planks are already *****ed, I hired someone to install and he could not complete the job as a part is missing, Now I have to recall him again which is another charge on me because of your mistake. Because your consultants are not getting back to me I decided to call again and email again this morning my mail was not responded to, my call was answered and the consultant confirmed that there was no return logged for the duplicate delivery, and that the supplier is out of stock for my stuff how can the supplier be out of stock when the consultant I spoke to on the 4th said he has contacted the supplier and waiting for a response? Also how can they be out of stock when The box i am missing is what I need to complete my set that box should be at the store as I did not receive the full set. I don’t know how you going to solve this but I need my missing box because I will not be un*****ing things on the wall and further damage my wall and have to pay extra for this guy to remove this. My house is a mess full of planks because I am stuck due to your incompetence