U visa

I had been living in us since 1997 I was deported about a month ago I was going to apply for the u visa as victim of domestic violence but since I have a previous deportation I was told by the bp that I had no right to anything and they deported me along with my 5 year old son I went to see an an attorney here in Tijuana he said I had no hope since I'm deported for 20 years and advised me not to waste my money trying my attorney in San Diego says I can still apply from outside of U.S. he said he will send the form I-198 and all necessary documentation along with a waiver package but I'm scared he just want to take my money and there's really no hope he's a really good attorney but I'm not sure what to do please I need a second opinion I'm desperate here in the border with my son missing school n crying because he wants to go back to San Diego thank u so much for any advise to see if can can get a waiver for my deportation n get my U visa approved or maybe not hope to hear from u