Unreliable info and waiting weeks for an upgrade due to no stock

I upgraded on the 13th April. When I did upgrade, the lady told me there are 13 units available. That evening, I got a sms to advise me there is no stock, i will receive a message once its back. I called to find out how there are now all of a sudden no stock. They work off an excell spreadie to check SOH (stock on hand) which is sent out daily in the mornings (not real time). which is kind of ridiculous considering the technology and size of the company, first of all. They advised me to call back in a week. So i did, where I was told no ETA on stock. Then I called again a week later. Lady told me anytime from the 15th - 25th. So I called again today. Now there is no ETA again. I am not sure how 1 person can give me an estimate, when now all of a sudden again there is no ETA. If you are working for the same company, I should get the same answers, or at least an update to say the date moved. At least provide an update and a reason for the delay as I have been waiting for a month now. I understand there can be delays but then advise the customer accordingly and don't give me different stories each time I call. This gives the impression you don't actually know whats going on. Not good!! And please, empower your employees and give them the tools they need to do their jobs properly, you cant have an upgrades consultant relying on outdated data sent to them on a spreadsheet, Give them access to the systems to check.