bad online and in store service

I am so disgusted in their service. For my 50th my mother who is 71 bought me a voucher online that was to be messaged to me. which i received on the 10th. yesterday we to the branch in tygervalley and selected clothing. at the till i am told the voucher does not work. they eventually phone someone and the problem was the correct unique number was not sent. i stood there for ore than 20 minutes feeling like a ******** when asking the manager whose fault it was she say online people but dont the all work for the same company.