All cells have compressed into one across all columns

i exported some data from a software program using their export function. i believe i exported in csv or possibly but could have been xls. i was able to save the spreadsheet once and open it and everything was formatted fine including some highlighting i had done and editing the data. i just opened it and all the formatting was gone and all the data that was in 50 rows and accross 12 columns all compressed into the first column. how do i get the data (that now seems to not have a seperator) back into the multiple cells/columns. i cannot replicate what i did to get the data in the first place.