Have they sent payment to you via Paypal? I did my best to translate without Google Translate (it really doesn't do well for many languages) and it seems that they may be saying that they have paid for shipping for each item alone, but they are asking if the items may be sent together to reduce the overall shipping cost, and have the subsequent difference refunded back to them.
If no payment has been sent, then I am not sure what they are asking. But I would start there maybe, if you haven't figured it out already. Hope this can help, and good luck!