I am an IT professional/ software developer, and have been self-employed since October last year.
When I first went self-employed, I only had the one client, and was working for them full time. After delivering the project to them, I had a bit of 'down' time while looking for my next client/ project. I have now secured my next project, and recently started working for that client.
However, between finishing working for my first client, and starting working for this one, I did a few days work (just decommissioning old servers & setting up new ones) that I got through a recruitment agency.
Basically, one of the recruiters at the agency had been in touch regarding a couple of roles he was recruiting for, and while those discussions were on going, he mentioned that he had a few days work available decommissioning & setting up these servers at the local court. He asked if I would be willing to assist with this work, and I said I'd be happy to.
This work took place over three separate days, and after the first day (there were a couple of weeks between each work day), I sent the recruitment agency an invoice for the work I had done, at the agreed rate, and was paid on receipt of that invoice.
However, following the next two days' work, I invoiced the agency in the same way as I had previously, and they then got back to me to say that I would have to invoice them through an umbrella company... But they had not mentioned that I would have to do this at all before I agreed to do the work, and they now appear to be refusing to pay unless I send them the invoice this way (I have had no response to emails sent a couple of weeks ago).
Since going self-employed, I have managed invoicing my clients myself, and would rather keep doing this, than pay an umbrella company a fee to do it for me...
How can I ensure that this agency pay me the agreed amount for the two days' work that I've done for them, which is outstanding?