I think 'I rang Megan' should be OK too; this is normal British English.
Please report any translation that you believe should be accepted.
Is this normal sentence structure in Welsh for the verb ffonio?
Based on Cornish, I would have expected Ffoniais i wrth Megan.
Yeah, this is the correct sentence structure, maybe it's because Cornish uses a more traditional Celtic word i.e Galwais i ar Megan (which isn't used for phoning somebody but it does mean "to call".
Thank you for the confirmation!