Make a phone call to the client and try your best not to be angry.
If they don’t pick your call, you can send a letter. Ensure that you maintain professionalism and politeness in the letter. Try not to antagonize the client. Itemize all the services you’ve provided for the client, the cost for each service, and the steps you’ve made to reach out to them.
Collect part payments. If the client states that they will not pay the entire sum, you can try collecting a portion of it. You’re better off getting something than nothing.
Consider legal action. When you realise that the client won’t pay, you can take legal action.
A letter from your lawyer should be enough to convince the client to pay up. It doesn’t benefit either party if the case ends up in court. This approach works if your customer has a means of paying but has not yet paid.
Alternatively, you can hire a collection agency.
You will have to pay a small sum to the collection agent, which is usually around 25% to 40% of the total.
You can file the case in a small claims court. 
Should you choose this route, you should know that if the client fails to pay because they have no money, then no amount of verdict in your favour will get the client to pay you.
Debt collection in a small claims court doesn’t require a lawyer. When the debt is a considerable sum, the court will hear it, but they may propose that you take the case to court. In court, you’ll require a lawyer to help you with the matter.
It would help if you considered the pros and cons involved in taking the case to court.
Do you have any strategies to encourage timely payments in your business?
Please let us know your thoughts in the comments.