Numbers beginning with 0570 are used for nationwide unified-number services, which let callers reach the same number from anywhere in Japan. The best-known example is "Navi Dial" from NTT Docomo Business (formerly NTT Communications). The caller pays for the call, and how much depends on the line the call is made from (landline or mobile) and on the calling plan. Charges from mobile phones tend to be higher. A recorded announcement before the call may state the rate, but rates are revised from time to time, so confirm the current amount with your own provider.
The point to watch most closely is that 0570 numbers are excluded from mobile "unlimited calling" plans. Even on an unlimited plan, calls to a 0570 number are billed separately, which makes it easy not to notice that charges are accruing. Billing also continues while the call is connected, including time spent listening to automated menus or waiting on hold. The longer the call center queue, the more it costs, so calling outside busy hours is one way to keep the bill down.
Companies choose 0570 numbers because a single number can take calls even when they have branches across the country, with incoming calls distributed among those branches. And unlike 0120 toll-free numbers, the company does not pay for the calls, which keeps the running cost of the contact desk down.
To keep charges down, look for a direct number with an area code (03-XXXX-XXXX and the like) on the company's contact page or on your contract documents and invoices, and call that instead. Calls to ordinary area-code numbers are normally covered by unlimited calling plans, but check what your own plan covers. Some desks publish no direct number at all, in which case the 0570 number is the only option. See Free Dial versus Navi Dial as well.