Obviously I can only give you a general answer as you haven’t come back.
Yes, you could sue over this.
If this is a limited company you can also sue the directors. They are liable if they acted fraudulent or negligently.
You need to write to them to demand payment within 30 days and say that if they do not pay you, you will issue county court proceedings against them. See here for a guideline
You can issue here
If this is under £10k then that is just a small claims court sum.
Even if it is under £25k the costs are fixed.
You claim for the sum of the loss, interest at 8% per annum and the cost of issuing.
If you succeed then they will have 14 days to pay in full and thereafter you can enforce using bailiffs if needed. You can also freeze their account or seek a charge on their property.
Can I clarify anything for you?
Hopefully, I have answered your query in a way that is simple and easy to understand. If anything remains unclear, I will be more than happy to clarify it for you. In the meantime, thank you once again for using our services.