Amex unauthorised charge

My business is a Ltd company which is a seperate entity from myself.

Over the past few months cash has been tight in the business and we’ve been behind on some payments.

There is a company that we owe around £2,000 to.

Earlier this month after speaking to them, I agreed to make a payment on behalf of the business to them for £1,000 from my personal Amex card. I absolutely did not have to do this as I personally am not liable for the debt, but I felt it would be a good thing to do.

Anyhow — it turns out that they have taken the £1,000 and subsequently 7 days later taken another £1,000.

This extra £1,000 that they have taken is owed by the business, but it is absolutely not owed by me and I never authorised them to make that transaction.

I actually have emails where they have asked if I would authorise it to which I did not respond.

My question is as to where I stand from a legal perspective around this unauthorised transaction. As my own money is tight right now, I really cannot afford this extra money that they have taken and feel pretty annoyed as I was under no obligation to help them out from my personal funds in the first place.