The info below is in relation to what has been pretty much in the public realm for some time now.
As those in the know, know Optus have been slowly re-negotiating all their MNVO contracts when they reach the end.
These re-negotiations resulted in Woolworths mobile going bye bye until it was re-launched using Telstra's 3G network recently with a much less attractive plan
So it seems in early 2016, it will be Amaysim, TPG Mobile and iiNet mobile's turn to re-negotiate their terms
On The Sky Business channel on September 2nd the CEO of Amaysim was asked directly about this and (i am paraphrasing here) he said:
While Amaysim has had an amazing partnership with Optus, as it currently stands Optus have indicated they would not be able to offer Amaysim customers the kind of value they have expected in the past. We would love to remain a long term partner with Optus but our customers have to come first, We have had preliminary discussions with Vodafone Hutchison Australia and we are confident that regardless of the outcome with Optus in March 2016 when our current arrangement ends we feel that we will continue to offer the best value plans in the market.
I am interested to know from people who use Amaysim, if they switched to Voda would you remain a customer?
I would remain a customer so long as my experience doesn't change. Bonds moved production to China, but my toes still love their socks. TPG also resells optus and I would never again use them for mobile! I've had nothing but good experiences with Amaysim.