Appalling service on a contract upgrade

What an appalling experience on an upgrade. Sales consultant sold me a double deal on a phone & tablet at a certain price. I received the devices and immediately started setting everything up, buying covers, chargers, etc. About a week later I was sent a preliminary billing with an amount higher than I agreed to.

When calling Vodacom to query this, they said there is no package at that price. I said but that's the price your sales agent sold it to me at. They escalated the issue and came back to tell me yes it's a valid dispute (in other words I was right) and I should return the devices and cancel the contract. I said I'm already using the phone and don't want the schlep of having to remove everything on the devices, put it all back on my old devices and pack up everything to ship back. Vodacom you are in the wrong, so please can you honour the price given to me. They said they'd give me more data which I didn't feel I needed. Their attitude was take it or leave it.

I noticed there was a double deal (same devices) at a similar price so I said just switch me to that package. Response - you'll still have to send the devices back, cancel the contract and take up the new deal. How totally retarded!

Long story short, they refused to give it to me at the price I was quoted and wouldn't/couldn't switch me to the other contract. I ended up returning the devices. I am furious. This is how they treat a long-standing customer who always pays their bill on time.

Not to mention the runaround I got trying to speak to the relevant person/department being pushed from pillar to post, navigating their annoying automated voice system which pushes you to their stupid bot, and the two calls that got cut off in the middle of conversation with an agent. Shocking customer service! Vodacom has lost my trust and my loyalty, two things you never want to lose from a customer. Poor show.