I can't put a check in the box "代表回線と同じ (same as the main line)" in the "ご契約者名 (contract holder's name)" field on the online application screen for sub-line inputting for "Omatome Seikyu Service (combined billing method)."
回答
Please select "本人 (himself/herself)" in the previous field "代表契約者との続柄 (relations with the main contract holder)."