Camaro91RS

alright so....ever since I bought my car a year ago......the speedometer wouldnt budge at cold then once the car warmed up, it would wobble inaccurately........So then about 8 months later.....I get a code 24 and realized it's time to change my VSS. So I went to autozone....they gave me the wrong one and I couldn't drive my car for 2 days until they ordered a new one......2 days later they order the wrong part AGAIN....so finally I just went to Murray's and got the right one. I came home, slapped it on, and my speedo was perfect......for about 2 miles. After that it just stopped completely. I was like wtf so I thought they gave me a bad part.....I took it back...got a new one and installed it.....worked for 2 miles again..then died. so for the last 2 months.....i've been driving without a speedometer, and a very often code 24. Any idea's on what to do, or what damage this could be causing me? Thanks guys