Rite Aid complaint: Short Changed me , Gave me change for a 10 instead of a 20

Picked up 3 Prescriptions , I had 3 20’s 3 one’s in my pocket. my bill was $9.71 I gave him a 20
and he gave me change for a 10 , I told him that I gave him a 20 and 3 times he said you gave me a10, and if you have a complaint you can talk to the store manager. So I did , I told him what happened
he said that he would count the draw, I said I had to go as I have a schedule to keep. He got my number and said he would call me. and he did, saying that the draw was only off by a Nickle, and there were not any 20’s in the drawer, I do not accept that answer , I only had 3 20’s and 3 ones in my pocket, The manager Named Jim had the Gull to snicker at me, and thought it was funny that I was upset. I want my money that you are holding from me . and more that likely I will be Transferring my Prescriptions to C V S I can’t believe you did this to me , I come to Rite Aid 2 or 3 times a week to get my meds. It hasn’t been the same since Jay left. I don’t care what anyone says
I gave the man a 20 and he gave me change for a 10.