1. Do not even waste your time with the company you used. Just by a few facts you mentioned, they are not following standard industry procedures when performing major work on equipment. Just accept it as a lesson learned and move on.
2. Call and get another company out there and let them know what all has happened so they know you are knowledgeable to proper procedures.
3. They should test your system for acid being you had a compressor replacement and no filter(s) have been installed, check your metering device for obstruction, check the static pressure across coil to determine if it is plugged.
4. After that, hopefully they will find your problem and they can go from there to resolve it.
5. There is a good chance they can save your system if they find it acidic. Just have them clean the inside with a good flushing with proper product, and filters installed, and then the large one removed the following day and keep changing until your system is clean. Make sure the little filter is changed each time they change the large filter.
6. Call a supply house of the brand of your equipment, and ask them for a reference for a qualified and trained company that knows what they are doing. Let them know you are knowledgeable and do not want someone who is clueless. Call the contractor and quiz them a little to see if they are open to these suggestions I mentioned, and go from there.