Lack of service / correspondence

I ordered online during the R10 sale on 3 August 2020. On 16 August 2020 I noted that they failed to deliver 1 item p***. To date I have not received a response to my initial request, despite follow up e-mails. How is it possible that a retail store is unable to locate a parcel and /or resolve a enquiry and now complaint within a reasonable time. It is non sensical to have a turn around time of 2 weeks to respond to queries during a limited sale period. Moreover, do they not have a process in place to resolve issues. It has been more than a month since my purchase, going on a month of my initial enquiry. Do they think that by ignoring me and keeping my money is justified?