I have given up recieving any more money from the amount owed and would not mind giving the files at this point just to get him off my back. Unfortunately, it

I have given up recieving any more money from the amount owed and would not mind giving the files at this point just to get him off my back. Unfortunately, it also doesn't seem like the client needs the original files anymore. Let me explain. Two weeks ago he offered $150 additional for the files. Clearly he found value in the work I had done so far. Now he has done a complete turnaround and argues that I just "strung along" and did not really do much work. That is obviously not consistent with him offering additional money two weeks ago for the originals. A lot could have happened in the two weeks he was silent. He could have easily given the jpgs of my work which he did have to someone to recreate it in photoshop. Thanks for the detailed analysis :)