I recently took my car into what is supposed to be the best garage in town (certainly, the most expensive). Foolishly, partly because of their reputation, I didn't take precautions I'd normally take like taking a photo of the oil state before going in, I just knew it was a slightly brownish amber colour and might need changing. I didn't question them when they said one of the things they'd do was change the oil and filter and fix a few related issues with the oil pan.
After getting the car back, it looks like they didn't actually do several of the jobs they were supposed to, and there are plenty of other reasons to be suspicious (for example, we agreed a quote including changing the brake pads, but they didn't change them, and it wasn't until after I'd come to pick up the car, after they'd told me everything was done, and after I pointed out to them that the brake pads were the same as when I took the car in, that they admitted or explained this and prepared a new invoice with the cost of the brake pads removed...).
I'm starting to wonder if they might have lied about changing the oil as well. This is a country with very low standards for mechanics, so it wouldn't be particularly surprising.
How can I tell if the oil has indeed been recently changed?
One thing I've tried already is to look at the oil using the dipstick, and it looks very similar to how I remember it being before taking the car in. Looking at various guides, to my eye it looks like it's somewhere between "fresh" and "should be changed". This car is petrol, not diesel where the oil often changes colour immediately after an oil change, but it is quite old ('97 Toyota RAV4) if that's relevant. I'm not sure if this is evidence it's old oil that was getting close to needing changing but didn't need it urgently, or if it could be new oil that simply discoloured a little naturally.
Here's a photo of how the oil is currently (I really wish I'd taken one like this before going in...), taken using the dipstick while the engine is cold. If the work was done, it was last Friday, and this photo was taken on the Tuesday morning after driving for about an hour to take the car home on the Monday.
Update - I've questioned the guy from the garage about this (and the other problems). He's insisting that any discoloration is because it's an old car, and he's (rather shamelessly) taking the opportunity to try to upsell me an oil flush... I'm starting to suspect that they did a very half-arsed oil change, just draining and replacing whatever came out of the sump quickly, possibly not even warming it first...