Without explicit agreements/laws in place I have to sadly agree, and any natural monopoly will get abused at some point if owned by profit-seeking companies. That's just how it is. Doesn't matter if they are now sweet-talking you into doing this deal, the fact is that once they are in the position of power, they can do whatever they want. Of course there are some limits what the customers can take, but when their end-goal is maximizing profit extraction it's just dumb to assume it will be all butterflies and rainbows.
As an example if you even need any, the government of Finland decided to let government-majority owned electricity company (Fortum) to sell off their electricity distribution (Caruna) to some private investors. I don't know what the investors promised but quickly after the deal was made, the prices started to rise, the company structure was made that the company in Finland is paying ridiculously high interest rates (8.5%) on loans to some Dutch holding company, with an effective tax rate of couple %.
And even in general, why do they have to sell .org? I don't see any concrete benefits whatsoever for the normal user.