I have given up too. I just try to live my Orthodox life, however badly. If people genuinely ask, I do my best to answer. But the pride stemming from one-upmanship arguments and the frustration caused by entertaining people's constant criticisms are detrimental to my own spiritual path and will not convert anybody, so I don't engage in them anymore.
When I first made it known in my former Anglican parish that I would be leaving for the Orthodox Church, the organist sat me down after choir practice one evening and grilled me for explanations, trying to persuade me of why I was making the wrong decision. His arguments actually spoke volumes about his own reasons for being in a church and showed how he could not possibly understand my own. He said that I did so much in the parish that I had a responsibility to stay. He said that sometimes he had felt like leaving but that he couldn't abandon the parish. I said that the parish had survived for over 125 years before I joined it and that I did not think it would suddenly collapse if I were to leave.
He told me that I had flitted from church to church (I had passed between a number of Anglican parishes in my journey) and that I clearly didn't know what I wanted. He asked me why I was joining something Russian, and said that he went to Russia and was horrified at all of the costly decoration in churches there. When I answered that Russianness had nothing to do with it but that I had to belong to the Church, he said that I could belong to the church I was already in and that there isn't anything specifically Russian about the Church, (completely misrepresenting my reasons, of course).
When I explained that it was because I had explored Christian doctrine and I could not see it any other way than the Church of England had separated itself from a number of Christian beliefs and that I just couldn't accept it as part of the Church any longer, he laughed in my face. He said that I could stay where I was and still believe my Orthodox beliefs, then went on to explain that, in his nearly 50 years in that parish, he had seen many clergy come and go, and had heard many different and sometimes conflicting things being preached, but that the Church of England could embrace it all and that I was no different. He seemed to be under the impression that this was a good thing.
The conversation went on, while he continued to talk at me.
I don't know what he thought he was doing but by the end of that conversation, I was not re-assessing my reasons for becoming Orthodox, I was not lamenting leaving the Church of England or my parish any more than missing some of the people, I did not feel that any of the reasons that I was leaving had even been touched on but that I had instead been subjected to a barrage of misrepresentation and nonsense. I felt frustrated, upset, belittled, and bullied, and I was definitely not encouraged to stay in any parish to which this man belonged. If he was trying to get me to stay, I think that his attempt was an utter and complete failure.
For a while afterwards, I regretted not being more forceful, and not being more articulate - having the answers at my fingertips so I could "win" the argument - but this was now some years ago, and I realise that rising to the bait from people like that is simply not worth it. Accept their criticism with as much patience as possible, then go away and pray for them. If they ask out of genuine interest, answer them with love. Otherwise, it is best to just live your Orthodox life and let that be the witness to the faith that they see. You never know what will happen years down the line.
I know of an Orthodox lady who converted some years ago from an evangelical tradition to which her whole family had belonged. None of them would go to her chrismation, she received criticism whenever something of significance happened in parish life and she wanted to share it. She decided to just quietly live her Orthodox life and treat them with love. She has a great nephew who was a very sick baby and she and I took him to a church when the Kursk Root icon was visiting. One of her sisters, (the baby's grandmother) came with us and refused to come into the church. Now, another sister, who was equally hostile towards this lady's Orthodox faith for years has suddenly started going with her to visit an Orthodox hieromonk for discussions about matters of faith, they pray the Hours together in church, and she says that she wants to come to church at least once a month. She is reading about Orthodoxy, and has apologised to her sister for being so cold to her when she embraced the Faith.
From St Seraphim of Sarov:
Acquire a peaceful spirit and thousands around you will be saved.