Double slash after domain name

Hello, my client did something amazing with his website, and pressed something on the dashboard that said Revert to Default apparently, but now I can’t access any pages – even permalinks or anything, without it trying to find his domain name https://timbudgen.com// and as it can’t find anything it just puts the header and a blank page. I can’t stay in the dashboard because it just goes straight to header and blank page. Anyone know how I can fix this and tell it to look for the right pages? I am guessing permalinks structure has changed but without being able to edit them I am a bit stumped. Is there a way to edit them via ftp? Thanks,