Please make sure that you use the correct seed phrase, even a single space or character (even if you clicked on the Return/Enter button when you were importing the seed phrase) will generate another waves address.
One seed phrase generates only one waves address. If you get different address it mean only that you imported an incorrect seed phrase.
By the way, the seed phrase always contains 15 words with spaces between each word. Except the beginning of the first word and the end of the last word.
For example (check attachments):
With one space>
With the pressed Return button
Customer support service by UserEcho