Does antibiotics always work for Chlamydia?

Wow, I really wonder what type of doc this "Doc" guy is. 1000 mg of azithromycin is standard CDC recommended treatment for chlamydia. It is usually effective, but you can be reinfected. You may want to get a second test just to be safe. Doc would be right if he were treating you for sinusitis or upper respiratory infection, but genital chlamydia is 1000 mg of azithromycin taken at one dose

Chlamydia sometimes is very difficult to cure. Its intracellular bacteria, and sometimes even after antibiotic treatment it might "survive".

I would suggest to perform another Chlamydia test, but after 1 month just in order to have accurate results.

I am bit surprised by the treatment prescribed to you. Usually Chlamydia infection is treated with Azithromycin, but the dosage should be like this: 1st day - 1 gram, 2nd, 3rd, 4th and 5th day - 500 milligrams. See other doctor next time.

You would either take Azithromycin 1g PO for 1 day or the alternative treatment is Doxycycline 100 mg PO for 7 days. Test of cure not needed. You should refrain from sexual activity for 7 days after completeing medication.