Contracting sting in the tail.

[d000hg]

As said, this is kind of normal and you need to phone. Going straight to solicitor's letter before you phone them is crazy. You don't even know for 100% sure your email got through and wasn't marked as spam. It happens.

You don't even have to phone up all cross and shouting, your first call can simply be a polite one to the finance/accounts department to enquire about payment for invoice XXX. Then see what happens.

I for one would love to hear a step-by-step how you approach this and what happens.

[NotAllThere]

As soon as the invoice is late - send friendly reminder, and noting that if the invoice isn't paid with seven days an admin charge and interest will be added to the outstanding amount. The Late Payment of Commercial debts (Interest) Act - Pay on Time

When that's not paid, another dunning letter, this time with admin charge and interest.
When that's not paid, another dunning letter, noting that interest is continuing to accrue.
When that's not paid, final demand, threatening legal action.

Always offer to discuss, if they've difficulty paying. The last two letters may be copied to the home addresses of the directors.

Usually be the last letter, they'll pay up. You'll probably not get the admin charge and interest, though they are a legal debt. Best to write that off.

The reason for following this process is that if it does end up in court, you've shown that you've been reasonable, which helps your case immensely. If it does go to court, then they'll have to pay the admin charge, interest and court costs. And when you've establised a process to follow, then it takes some of the emotional heat. "Nothing personal, it's just the dunning process my company follows".