If you bought the camera on Ebay, and it was payed via Paypal, you have 99.99% chances to get the refund, if you claim (with photographic proof) that the item was not "as described".
If you decide to keep the camera, the fungal infection, as i see it from the picture, should be cleanable.
I haven't added te words "for sure", because with coated glasses there is a certain degree of uncertainity. With most fungi, the glass gets etched only after a good amount of time, while the coating gets stained more easily.
In general, the danger of fungi is grossly overstated. I have a large number of "user" lenses, plus a collection of large format vintage glasses (more than 100, i guess, i haven't counted them), and some of them had some sort of fungus: every single one came off perfectly cleaned!
I use ROR (residual oil remover) as optical cleaner. If a large quantity of fluid must be used, i spare some ROR, going first with white vinegar.
I even bought an anti-fungal powder (for medical use), to prepare a washing solution to clean the barrel of hugely infected lenses, still haven't found the need to use it, though.
I am no Rolleiflex expert, but i guess that a standard adjustable lens spanner is more than enough to remove the back cell of the lens. IIRC the 2.8F does not have a tessar, hence you could be unlucky, and have to dismantle the cell to get access to internal surfaces.
Of course any good repairman could take care of all that, for a reasonable price and quicly (if the fungus is not a "difficult" one).

have fun

CJ

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