Oleksii As stated above, you always keep your accounts and cards when changing plans. Nothing is deleted or changed without you actively intervening. Which means your IBAN(s) stay the same and your card numbers stay the same.
That being said, some cheaper plans might have lower limits, so if you open 10 sub-accounts on for example the Easy Money plan, then don't expect to be able to keep them all when changing to Easy Bank. But in your case with 1 sub-account and 1 card, that's totally fine with the Easy Bank plan. There should be no issues with changing to it.
You mentioned that the app asks to delete an account... are you still facing an issue with the plan change? If yes, it would be nice if you could further specify what you're trying to do and what exact error message appears.
