Took My decoder into DSTV and all swapped out fine, get home and have an error message stating signal issue/ faulty installation

Took My decoder into DSTV and all swapped out fine, get home and have an error message stating signal issue/ faulty installation. Phone DSTV to see if there is an installation setting that needs to be changed but they insist that I must check my installation yet the only thing that changed was the decoder, why must I "pay" for someone to come out and fix an issue that wasn't caused by my setup.