Toyota Repair: Oxygen sensor problem, toyota camry, oxygen sensor

Question
I replaced an oxygen sensor because of PO135(Bank 1 Sensor1)trouble code on a '99 Toyota camry with 58T mi on it. A mechanic changed the sensor on top of the engine I cleared out the code and the code came back on again. I had it checked again and it had the same diagnosis. What could be wrong with the car or could the sensor be bad. I can't take out the new sensor and replace it with the old sensor to check it as the mechanic stripped the old one in removing it.I also had a clutch problem with the same car. I had the clutch replaced and had a burning smell afterward and after two mos had to teke it back for further diagnosis with the slave cyclinder being the problem. I asked the mechanic why he hadn't changed the slave cyclinder along with the clutch and his reply was that I hadn't told him to. He claims that I burnt out the new clutch and I was told that I couldn't have burnt out the clutch in 2 mos. Can you comment on this?  

Answer
First of all, you need to not deal with these people anymore and take it either to another shop or preferably a toyota dealer, it sounds like they replaced the wrong O2 sensor, is this a V-6 engine and if so can you tell me whether the sensor near the radiator or the firewall was replaced?
The statement the mechanic made"you didn't tell im to" is redicilous and unprofessional, you are not supposed to tell the mechanic what to do, you are supposed to tell the shop what the problem whith the car is and then they should make a diagnosis as to how to repair that problem.