Seeking information on tax invoice - not sure of the rules

...in this case.
I had some household stuff shipped from Australia to Japan in May. I have done so prior to this, last year. I requested a quote from the shipping company, same as I have done before, and paid them for their shipping services, as quoted, for my goods.
I had been told that I wouldn't be charged any additional charges upon delivery as the items were used/personal goods and wasn't with the first shipment.

This year in May we had another lot of stuff sent and received them in May. Paperwork was started and sorted with everything paid in April.

I received an e-mail from someone at the company here last week saying there were additional charges to be paid, no invoice attached or anything, quote "Will you accept these charges?" to which I said no, I had already paid what I was quoted and knew I was not going to be charged any sort of tax on the goods entering the country as they were household effects. Basically, I had no idea what these charges were for, he didn't actually send me an invoice, just asked. I didn't hear from him again after that. Cool.

Today I was cc'd in on an e-mail to that same man from the receiving agents in Japan, asking for payment of this invoice.

My question (sorry for the essay, just wanted to be as clear as I could without rambling unnecessarily) is can I now be issued an invoice 6-7 months later ?
I feel ditzy having to ask but I'm just not really sure of the laws and rules about this sort of thing and hoping someone smart here can advise what may happen now and/or what I should do.

Cheers

Awww, nobody ?
No-one can help me or have any thoughts on this ?

I don't know anything about Japanese law, but that does seem strange to me. If these were just your household items, I can't imagine they would tax you for it at all, let alone months after delivery. I'd probably just send him a copy of the receipt and say already paid in full.

Unless the government comes after you for taxes themselves, I don't see any reason to pay this guy. It's questionable if it's even a legitimate charge.