Yes. The Quran warns against breaking oaths after making them firm (16:91), and warns those who sell Allah's covenant and their oaths for a small price (3:77). Swearing by Allah on a lie, in order to take money or a right, is a major sin.
And fulfill the covenant of Allah when you have taken it, [O believers], and do not break oaths after their confirmation while you have made Allah, over you, a witness. Indeed, Allah knows what you do.
Indeed, those who exchange the covenant of Allah and their [own] oaths for a small price will have no share in the Hereafter, and Allah will not speak to them or look at them on the Day of Resurrection, nor will He purify them; and they will have a painful punishment.
This is general information, not a fatwa. For your own situation, ask a qualified scholar.
Questions about halal and haram
Is swearing a false oath haram?
Yes. The Quran warns against breaking oaths after making them firm (16:91), and warns those who sell Allah's covenant and their oaths for a small price (3:77). Swearing by Allah on a lie, in order to take money or a right, is a major sin.