Came here to get an oil change, first time here. I...

Came here to get an oil change, first time here. I usually go to my car dealer to get it done. I hear Walmart does good oil changes. When I arrived they looked under the hood and told me my car ONLY take synthetic which is a lie because I use penzoil all the time I know synthetic is better but that's not what I wanted, they also stated I use a special filter which would be an additional $10. I expressed my concerns to the automotive manager Alex who I asked to print me out something stating my car only takes synthetic oil he said there wasn't anything saying I had to get the synthetic oil but if I didn't he would decline my service, then who looked up my filter it wasn't $10 it was $4. I feel as though they were trying to make extra money off of me, taking advantage I really hate feeling like I have to do something especially if it's not required . How can they just do this? Worst experience with walmart ever in life . Nothing made sense here