Mudjacking / Concrete raising costs in northwest Chicagoland

[Mario Jay]

Hi everyone! 

I have a rental property in the NW suburbs of Chicago and the concrete running alone the house has sunk. The area of the concrete is about 40foot by 11foot. Each slab is 8foot wide for a total of 5 slabs down the length of the house. By the house the concrete sank about 3 inches while the other end is still "level". 

My question is twofold. How long would mudjacking last? I have had mixed reviews. Some people say it will last forever while other tell me it starts to sag again after a year or so. The second part would be associated with costs. For new concrete I was quoted about $7/sqft all in. How much does mudjacking usually cost? Thanks in advance!