did you take all the steps as specified on the actual form 4852?
https://www.irs.gov/pub/irs-pdf/f4852.pdf
You should have furnished the IRS agent with the required info and so they would then have attempted to contact SVT. Do you know if the iRS attempted to contact SVT?
did you fill out a W-4 or W-9 when you started to work for them? if so which or was it neither?
do you remember if the paystubs showed social security and Medicare taxes taken out?
with this info it would be easier to offer a suggestion. But we have no better info than you. so whatever is suggested will be a guess. No sense in using a pro they would ask the same questions and still would be guessing.