Cash App complaint: Merchant did not perform service she was paid to do and Cashapp will not provide customer service

I paid a merchant a deposit for my nails. She did my nails on June 23 and 5 of my nails came off 3 days later. I contacted the merchant and she told me there would be a $2 charge per nail to repair them! This is unacceptable seeing as how nails should last 2 weeks at the very least and should not slide off easily. I was completely scammed and did not receive the service I paid for. My entire left hand fell off. She refused to refund my $28. I went onto cashapp and tried to cancel the transaction which Cashapp says online that I should be able to do but but I was not able to cancel it because a cancel button was not there. I also could not, dispute or reverse the transaction or any transaction. Cashap should allow dispute transactions if they are going to be in the banking industry. Things should not just be irreversible when it comes to people’s money. Further, Cashapp has no customer service support of any kind. Even if you look online it says you should able to reach customer service by logging onto the app. and clicking support, then something else, but when you follow those steps, it never reaches a person or platform to where you can dispute your issue or get an answer to your question from an actual person. If I had known Cashapp does not have customer service, I would never have signed up to use this app. I demand that Cashapp allow me to cancel this transaction or open a dispute for this transaction to get my money back.