I got divorce by proxy in Bolivia. The two of us were in US but my mom through a power of attorney ran the divorce and went through. After several years i got married and uscis is tellong me that my marriage is not valid because my divorce is not valid. Is that correct??
This is actually Family Law question. You need to ask a Family Law attorney who practices in the State that has jurisdiction over the marriage whether or not dissolution by proxy is permitted in that State, & find out if the proxy followed proper procedure in filing the dissolution petition, etc.
However, if your divorce is not valid in the State it was filed in (due to a technicality, failure to file the final judgement, etc), then your subsequent marriage would also be invalid, causing the I-130 to be denied.