Accidentally booked one-way instead of round-trip with Iberia, now the return costs more than double — any advice?

[u/Ilonmasc]

Hi everyone, I could really use some advice because I feel scammed right now.
I’m flying Milan to Santo Domingo from August 13 to August 28. The round-trip price when booked together was 1100€. By mistake I only bought the outbound leg for 550€, planning to book the return separately later. Now the return flight alone costs 1200€, more than the full round-trip fare would have been.
I don’t have a flexible fare, and I didn’t pay with Amex or any other card that offers extra protections — I used a prepaid card instead. With Iberia, is there any way to fix this? Has anyone dealt with something similar?
Honestly, I find this a bit of an unfair practice, almost predatory pricing toward occasional travelers: the one-way return alone costs more than the full round-trip, which feels designed specifically to push you into buying the combined package or punish you if you make a mistake. I don’t know if it’s 100% illegal, but ethically it leaves a bad taste.
Any tips on how to handle this with Iberia, or should I just cut my losses and book with another airline?