My partner was posotive for chlamydia but my results came back negative even though we had unprotected sex numerous times, can test be wrong?

Yes. A sample is taken and tested. It is not always indicative of the entire genital tract, either male or female. You both should be treated for chlamydia to ensure that you are not passing it from one to the other.
Quite common. This happens a lot: positive in one partner, neg in the other. The test misses a few infections. False positive results are rare but possible, i.e. partner not really infected. Over time, the immune system clears infections without antibiotic, so it might have been there bu tnow gone. Both partners always need treatment, even if one tests negative. Good luck!