Radiocarbon dating is a tool used for dating plants, plant eating animals, and preditors that eat plant eating animals. Everytime I read that "radiocarbon dating has been proven wrong" its always something completely rediculous - like some creationist saying a diamond was dated as being only 60 thousand years old. Obviously you can't carbon date a diamond as they don't absorb C14 from the atmosphere. It would be like saying hammers have been "proven wrong" because you can't boil water with them. Obviously hammers are a tool used for driving nails not for boiling water. Likewise, radiocarbon dating is for dating plants and animals not for dating rocks.
But to come to the point of your OP, the simple fact is dendrochronology (using tree rings to date trees) has verfied the accuracy of radiocarbon dating up to 40,000 years. And scientest often use multiple dating methods to veryify the age of things. When they need to date something older (or something inorganic - like a fossil or rock), they have other tools they can use. There are several other dating methods including:
Obsidian Hydration
Paleomagnetic / Archaeomagnetic
Amino Acid Racemization
Fission Track
Oxdisable Carbon Ratio
Electron Spin Resonance
Cosmic Ray Exposure
Varves
Cation Ratios
Stratigraphy
And the other kinds of Radiometric dating:
Potassium to Argon
Rhenium to Osmium
Lutetium to Hafnium
Samarium to Neodymium
Rubidium to Strontium