Ok not sure if its possible to fix bug at this point. At the part where i return to quest giver and hes dead . Theres a quest marker next to him but no guards to arrest me. I tried a couple of things (xbox)

Got arrested- not a lot if dialogue messages and quest marker outside

There are no markarth guards?

Ive killed alduin and at the greybeard meeting markarth is given to stormcloaks.

I left city, waited 1 day and retried with no luck

I reloaded and no luck

Any solutions?

So your contact is dead in the temple of Talos but there are no guards to arrest you?

if there are no guards in there to try and arrest you then I'm afraid you might be in trouble there. They are suppose to spawn with the body and try to arrest you. If that has not happened then the outside guards will leave you alone.

can you reload a previous save or is it to late for that?