Unacceptable service

I received terrible customer service from this place! They serviced my car in December 2018, and I am still struggling to get an invoice from them. I have contacted the mechanic several times and he keeps saying he will mail it to me. I have been asking for four months now for the invoice. Also, they did not service all the parts on my car which I paid for. I had to ask another mechanic from another company to correct their faults (SNF Auto did pay the mechanic themselves). They also did not stamp my book and they also keep telling me the mechanic will come to me to stamp my book, but I have been waiting since December. This is unacceptable.