For payment of road tolls, there is separate Skytoll OBU which can be connected with DKV card. It is possible to order pre-pay or post-pay OBUs.
https://www.emyto.sk/web/guest/toll/calculator
DKV invoices include a statement of tolls paid in Slovakia, but this statement is not eligible for a VAT refund.
Invoices eligible for a VAT refund can be downloaded from the website of the Slovak service provider: https://www.emyto.sk/selfcare/logon/