Should be in your yellow pages closest BIG town or search online. Our lab is gone, old guys all retired, we did alot of mail order and turned around the average torque wrench in under a week.
Id request BEFORE AND AFTER READINGS, make sure they disassemble the wrench, check for broken parts, and lube. We kept parts in stock for just about every torque wrench on the market. These should be checked throughout the range, not just a one or two places. Also be sure to store the wrench with setting at ZERO and don't toss it in the parts washer it'll dissolve to lube.