I received a text saying you guys are no longer doing lease plans. It also stated in the text that I have to return the phone and buy it outright from Optus. My 2 year lease has just expired and in that lease contract I’ve been paying for the handset each bill so why do I have to pay for it again now that my lease has run out?
The reason Optus has stopped doing leases is because they have had the effect of misleading a lot of customers just as you feel. They were often sold as 'cheaper' plans because customers got an extra discount of $10 a month. The reality is that for that $240 'discount' you must hand the $1000+ phone back to Optus in very good condition (no major dents or scratches etc.)
So unfortunately you don't own the phone even though you have been paying almost the same amount of money as people on 'Pay for your phone' plans. At this stage your options are as you have described - hand it back in or request a payout figure (which should be reasonable for the second hand market)