Suspended pending investigation

So I have a question. How long does suspension with investigation take? For reference last week I had to go to a Valentine's Day meeting and another store to train, my store leaders keep swearing I got mileage then one tried to say I didn't so at the training store I made sure to ask proper procedures on time card and mileage so they told me because they were told by HR proper prodcedure, flash forward to when I got back to my store after telling my managers multiple times what I was doing and they ignored me so when I got back I got in a mini fight with my asl and dept head but the next day when I was pulled in the office over a different problem I asked my asl did I do anything wrong she dropped it and said no because I was already paid but the person who cashed it out was at fault. So I had my 2 days off then yesterday when I clocked in I was in for about 2 hours before I was pulled in the office and pretty much got told either resign or take the suspension so I took it and reached out the other store and they said I did everything right and they'll send them to the people who told them that procedure but when I called HR she had no idea and kinda ripped me a new one but with inventory Tuesday and Valentine's Day right around the corner and the fact nobody knows how to do it would they lift it by then or continue on? Cause I still have access to everything and haven't been told anything and I did email her everything that happened