Hey there @Rach-33. In a situation like this, it would be best to return to the Harvey Norman store of purchase and explain to them the matter at hand. In saying this though, we cannot provide any guarantee of contract reversals or refund. Alternatively, you can have the account holder contact our Customer Care Team via 133 937 to discuss this in further detail. (Mon - Fri: 8am - 8pm and Sat: 9am - 5pm).
Thank you for letting us know @Rach-33. As this is the case, I recommend waiting on a response from the store to see if they are able to get to an outcome. Or as you have mentioned, the suggestion of trying to sell the current Huawei device can work to recover some of the device costs to cancel the contract, if you do end up choosing this route.
"Would I have any grounds to cancel this plan and get a refund?"
No grounds unfortunately other than just politely asking. Unfortunately its very likely you will be turned down. The transaction involves, Apple, HN and Optus and a plan etc. and the general Optus approach is its yours.
You can end the Optus plan at any time with no penalty (its month to month). When you do that the full amount for the phone will come due. Your best bet then is to sell the phone as brand new on eBay or the like. You'll lose a few $100 but its not a disaster.
Note don't cancel the plan until you've ported your number to another plan if you want to keep it. You can 'park' your number in a $10 for a year Amaysim plan if needed.
What Optus plan did your (tech geek husband?) sign you up for? What sort of monthly data usage do you generally have in practice?
We haven't got to the advice part yet 😀
Telco post paid plans are extremely bad value for low (I'd say normal but that's just me) data users. But if you get a payment plan for the phone then you're forced to chose one like the $40 a month 10Gb plan (or about $1000 over two years). In days gone past the phone plans actually subsidised the cost of the phone but these days the two costs are completely separate. You pay the same for the phone either way but on a plan you can pay it off over several years.
For the iPhone I'd suggest getting it direct from the Apple website. They have a interest free payment plan and the cost is the same. The delivery process also seems much better. There is a small monthly fee ($5?) but that goes away as soon as you pay off the phone. You said you're happy buying outright anyway so you could just do that or perhaps pay it off over a few months if you want.
For users needing 10-20Gb then your better bet is a 12 month prepaid plan. Neat as you can use 5Gb one month and 20Gb the next and it all averages out over the 12 months. Also a lot cheaper. Some options include:
Definitely better than paying $1000 for the same.
Good Luck with the exchange