How to proceed when reviewers reject your manuscript but you believe there is no scientific basis for their objections?
You can complain to the editor, but you should not expect too much from it. Remember that reviewers work for free, so unless there are a lot of complaints about one reviewer, the editor will not take action because the reviewer would just stop reviewing for this journal. Moreover the editor, who quite often is  also working for free, may not take your complaints seriously, or judge that your case is not important enough for him to invest some hours of work - remember that he has to read your article to judge your case.

So the easiest thing to do is to submit your paper somewhere else, there are plenty of possibilities. However, if it is rejected again, and you didn't aim at the best journals, you should think really hard about trying again. There are many articles that should not have been written.