How to get a refund please?

Hi yall, I bought some bitcoin a few months back because my friend told me how it was the future and I needed to buy them.

It’s not working out how I thought it would at all.

How do I go about getting a refund. It was quiet an expensive purchase so I’d like to get my money back.

I have a few other coins I would like to get refunds on, the one with the dogs on them doggy coin and shib in you coin.

I have asked all around the local shops in town but no one seems to know anything about them. I have tried phoning my friend that told me to buy them but his phone must be broken because when he answers he can’t hear me.

Thanks in advance