Maksim - please dont resort to profanity it serves noone. I understand that you are upset, puru understands that you are upset. However try to find a more professional way to converse without the profanity, you will get farther and be more productive to your goal doing so.
Puru, you certainly can run your business any way you want however im not sure pulling a license for profanity was the right move. You dont have to listen to it and you can always refuse support and we all do that. But the client paid for the plugin and using profanity does not change that. Tell Maksim if they continue to use profanity once more than you will no longer support them, which is the way we all do things once it is pushed to that level.
None of us like getting yelled out, and fortunately it very rarely happens to me. However if someone was to do that, i would warn them 3x and if they continued i would not pull the license i would just tell them no more support, dont contact me, dont talk to me and i will block all your messages from now on. That is how you do it, you should never pull a license unless they physically threaten you or your family or your business in a physical harmfull way in which you feel your personal safety is threatened, that is when you pull the license and say bye bye.... But along with that you give them their money back too. That way there is no reason for them to come back on you and call you names like scammer.
To both of you - behave yourselfs and take care of this situation. Part ways and dont look back if you have to. Refund the money - tell them to delete the plugin and all copies of it and term the license and then part ways. Or work things out - get it fixed if its broken - talk professional - be professional - and get this done. There is no reason this should drag on this long - get it done......
and thats the short version of what i have to say lol....
both of you take care and be good....
Being upset is a part of life, part of business at times, there is no reason to use profanity and to be unprofessional.