Feeling harassed and no answers provided

I was in the process of applying for funding with my employer, it was the first time applying. An obtained a quote from the University, whilst in the process I received a call from enrolments informing me that my employer paid my fees. I was unaware of this an they proceed to inform me that my employer paid I should register for the online course, this was a telephone confirmation from them. I would assume with such information being disclosed to me they had all the relevant documentation including proof of payment before informing me of such. I proceed to register for one module, a few months later they start emailing my employer demanding the funds be paid and for proof of payment and even threatening legal action. My issue is that the university insisted the my employer paid and I would have never registered had they not informed me that I should proceed and giving me the information they did. The problem is also how there is still a positive credit value of funds I haven't used however they are claim the full amount that I quoted for with interest. I feel helpless because I am not getting answers firstly on why they gave me the go ahead to register had they not received the relevant documentation that being proof of payment and secondly claiming that we are liable for funds I haven't even used. Our names are being dragged up and down, I am so disappointed