Yes, exactly this. Don't touch the code right now, just tell them you are stopping ALL work until you receive payment.
Also, (kindly) remind them that as they have not paid for your work, it is actually your IP & they cannot use your software.
And dear God, please PLEASE use this as a lesson & start to better manage your invoices. I use Harvest getharvest.com & it manages follow-up emails for late payments automatically. You could use any system though - they're well-worth the $10 p/m.
Comments
Yes, exactly this. Don't touch the code right now, just tell them you are stopping ALL work until you receive payment.
Also, (kindly) remind them that as they have not paid for your work, it is actually your IP & they cannot use your software.
And dear God, please PLEASE use this as a lesson & start to better manage your invoices. I use Harvest getharvest.com & it manages follow-up emails for late payments automatically. You could use any system though - they're well-worth the $10 p/m.