Trying to understand ... you attempted an upgrade from 3.2 to a higher 3.x only to discover hosting wouldn't allow changing DB server config. Right so far?
You did begin by backing up the DB (sql dump) and a backup of code directory right?
So in reverting back, one would have to restored the original 3.2.x DB and the original 3.2.x code directory and that's what you put back. Is that right?
Through this attempt the same moodledata directory was being used ... soooo ... if above is accurate, then suggest manually removing contents of moodledata/cache/ moodledata/localcache/ moodledata/sessions/ then, for good measure, restart the apache service. On your work station being used ... clear cache/cookies etc. related to the site.
Then attempt accessing the site to see if one can get the old site with admin menus.
'spirit of sharing', Ken