artık türkçe yazmıyosun türkçe bilmiyosun galiba

My try as learner:

You don´t write in Turkish anymore, it seems you don´t know Turkish.

My try 

well then /from now on/ now you are not writing Turkish, it seems you don´t know Turkish

Or something like that.......... I´m not too sure if my translation is correct so probably best to wait for someone better to help

Oh and it should be yazmıyorsun and bilmiyorsun

 Sorry tomac, I didn´t see yours, you got there first.  I think yours is more correct than mine

Thanks and, of course, there is no problem

Anukete - Unfortunately, as a learner, I can´t be quite sure about my attempt, but lot of our forum members have much better knowledge of turkish, and very often they help in translation requests. We just have to wait for them to appear

 teşekkür canım..... and I´m the same! haha

I think you´ve both conveyed the correct meaning.

Thank you for help

 Thanks canım

 your welcome