Upgrade through call centre

I have been trying to upgrade a line since last month, when we initiated it then I was told I'll get delivery within a week. Thereafter kept getting told there's no stock. When following up with the agent I dealt with he kept telling me still no stock until about a week ago I got tired of waiting as all the shops have stock I phoned and spoke to a different agent who informed me the upgrade was cancelled last month and there was no upgrade on this line (so not sure what the 1st agent was doing), now that he was caught then he calls back with a story that he can do the upgrade and he'll call The Glen store manager for us to collect the devices there as they will have stock. We contacted the store and The Glen manager did not receive any communication from anyone about this arrangement, I also spoke to someone at vodaworld shop who confirmed they can't do the contract from 1 side and collect devices from the store. Then last Friday morning all of a sudden all the stock is here and he can initiate the upgrade and send stock after how many promises, cancelling the line, saying we can get it at The Glen but not making arrangements (if I didn't call and speak to a different agent I might have still been waiting and getting the same excuses). Saturday we spoke he was going to get the delivery finalised on Wednesday (today) and promised delivery done by Friday (29/12/17). Again empty promise. A confirmation agent calls today surprisingly same name 'Emmanuel' and sounds the same also makes a lot of promises but assures me they different people (feel sorry you have 2 people so alike). He now tells me delivery can take 3-5 days so might get it Friday but probably Monday. Now there's my problem again I was promised delivery on Friday, now it's a maybe. Then it will get pushed again to next week and Monday is a public holiday so will be anytime only from Tuesday. I'm really tired and fed up with this service all the empty promises quick to sign us up for contracts and upgrades and thereafter pathetic service and none of your staff will be held responsible for their actions because that's how your business operates and what they expected to do so there's no repercussions for anyone.