I agree, you will not end up in business class on neither SK nor UA with this booking. On SK it will be Economy Extra and on UA it will be plain Economy with an option to pay for upgrade to Economy Plus.

If your original booking with SK was in Economy Extra I would certainly complain and if no convenient rerouting is offered in at least a class similar to Economy Extra, I would ask for a refund.

If you were in Economy I would be quiet and happy for the extra miles you will receive on SK and UA as apparently you have been booked into a fare class that earns 150% on SK and 100% on UA (I assume that EB is your FFP - it might be different on other FFP)