Did you get a different pulley ? If not you can temp run the ribbed side of belt on flat pulley ... I've heard that it will stay and I've done it in testing but not on a road run for long period of time under load ...
^ like he said, you'll need to get a ribbed pulley off any similar Toyota from that era that's got a grooved pulley, I think mines from a 88 Tercel or something.
You'll also need to put the belt on the other side of the pulley now, and turn the bolt the opposite way of before to tighten it.