A pilot reported a NMAC while conducting a straight in approach in communication with Tower.

Narrative

I was inbound; straight in; for Runway XX at ZZZ and talking to Tower. There was another Saratoga on frequency also talking to Tower. However; its communication radio was very noisy and distorted. Both ATC and I were having difficulty understanding the pilot's transmissions. It appeared the other plane was ahead of me however I didn't see it. Then that plane's transmissions stopped totally. It also disappeared from my onboard ADS-B display. Tower issued it a landing clearance 'in the blind'; with no reply. As I continued the approach; I began to wonder if the Tower Controller had seen my plane and mistaken it for the other one. I was about to report that I was uncomfortable with the situation when the other plane passed below me from my 4 O'clock to my 10 O'clock position. VERY CLOSE both horizontally and vertically. I reported this to ATC and was instructed to break off and enter right downwind for Runway XY. I did this and landed uneventfully. It's possible that ZZZ1 radar was inoperative at the time which would have been a contributing factor.