What Happens Now?
Let's continue with the same example:

First of all, you have ensured the exchange rate of 1.0700 for the period ending 30 days from today. Nothing can change that. Such assurance has cost you, at the most, the original USD 120 premium you have paid.

The OPTION deal ends when you either execute your ensured rate sometime during the "open" period, or at the end of the pre-defined period.

Let's examine what happens when the deal ends, using various scenarios:

[1] You kept the OPTION for the whole period, up to its maturity date:

[1a] The EUR/USD SPOT rate is 1.0400 - you end up with a profit of EUR 270 (net profit of EUR 150, after deducting the PREMIUM paid).

[1b] The EUR/USD SPOT rate is 1.1000 (actually - any rate higher than your STRIKE of 1.0700) - you lost the PREMIUM you paid, nothing more.

[2] You may always execute the OPTION during the period, before the pre-defined 30 days.

The results (the amount you get) will reflect the difference between the SPOT rate of that moment and your pre-defined STRIKE, as well as value for the time remaining to maturity.