I noticed unknown devices being connected to our wifi. Went to the website to block them through MAC filtering. I entered the unknown device registered MAC address and then, accidentally clicked the 'allow the stations specified by any enabled entries in the list to access'. After that, my access to the wifi was denied. Tried my laptop and phones to connect but it's not working. Is there any ways to fix this problem? Can I just reset the router? Please help. Thank you! 

ps: already contacted ISP but he said he isn't sure about it because it never happened before to his other clients. I'm waiting for him to fully be available to help me.