There's no more that you could have done to sort this out. A pretty small issue to start with along with a very simple solution to fix it. The customer should have given you a chance to fix it. The fact they've not, and then have gained legal advice so soon in the issue suggest they're just not wanting to pay. And any court will see this.
I'd give Invoice Chasing | Chase Invoices | Failed Billing | Invoices Chasers | Credit Control | Credit Management a bell and tell them Dan sent you from the forum, explain everything, send them copy's of the letters (always always always keep the originals yourself) and let them give you some advice and help deal with the issue if they need to. They have legal bods in their company (my contact is one, they've done T'c and C's for all the forums).
Courts don't like customers withholding money. The correct way to deal with this is to pay for the works that have been done and then stop if there are more to be done. And you should get full payment for what has been done, and only then can the customer argue that works are substandard via a court to get any costs back. If they have held payment back fully, they're already on a loosing streak.
I'd give Invoice Chasing | Chase Invoices | Failed Billing | Invoices Chasers | Credit Control | Credit Management a bell and tell them Dan sent you from the forum, explain everything, send them copy's of the letters (always always always keep the originals yourself) and let them give you some advice and help deal with the issue if they need to. They have legal bods in their company (my contact is one, they've done T'c and C's for all the forums).
Courts don't like customers withholding money. The correct way to deal with this is to pay for the works that have been done and then stop if there are more to be done. And you should get full payment for what has been done, and only then can the customer argue that works are substandard via a court to get any costs back. If they have held payment back fully, they're already on a loosing streak.