Popular Maruti — Car Service quality

I given my Maruthi 800 car for service last week to Popular service centre at Mannanthala, Trivandrum. I got back the car on the evening. After 4 days I found the car tyre pressure was only 15 psi. Another local workshop asked me, did I replace the fuel filter? This is the type of service popular do? May be they have lot of new cars to attend, but when you take money you need to do correct service the old car also.