Virgin Mobile very unreliable

After struggling to upgrade to the phone of my choice, and being offered lower-range models as my only options, I visited the Virgin Mobile website where a range of upper-range models are advertised. After requesting a particular model, I was told there was no stock. I then contacted their new client department and was offered the upmarket phone in question with quick delivery. I am still waiting. Today I phoned Virgin Mobile, held on for an inordinate length of time, and was told that I could definitely expect a call from the upgrades department before 17.00. I am still waiting. I find the above scenario unacceptable and of concern, as I am already in my first month of a new contract upgrade without my handset.