Buying a plane

I need a plane to flatten boards for my table, so I have been shopping around. All that seems to be available is the Stanley no. 4 planes. I want a larger plane, preferrably a No 7.
I've been to numerous shops, starting with a few pawn shops in the area. My thinking is that most second hand planes should be good. A plane could/should last a lifetime!?! Not so?

I eventually found a larger plane at the supplier where I bought my table saw. New.
I was well pleased, since I am happy with the saw, although the price is a bit more than I wanted to spend initially. But, I need the plane, cannot find one anywhere, so let's go for it.

The plane in question is a No6 Jack Plane by Industro. I have no idea about brands and such, but I reckon that if Pretoria Tool Center are selling them, they should be pretty decent.
Wrong.
I brought my new plane home, and immediately was upset. The bolt on which the blade-depth screw turns, was completely stripped.
I called up the next morning and the manager tells me to bring the plane back, he'll swop it out.
I drive all the way to center of town the next day. The one other plane he has in the shop, has exactly the same problem.
I should have cut my losses right there.
Instead I allowed him to replace the defective bolt and screw, with a similar part from a smaller plane. I headed home with my fixed-up, brand new No 6 jack plane.
Pfffft.
I tested it and tested it, and for the life of my I could not get the blade square. It kept digging out chunks of wood with the right-hand edge of the blade, no matter what I did.
Let me make it real clear right now .. I am no expert when it comes to woodworking, but I am not a complete idiot. I can figure most things out.
I eventually took the blade out for the umpteenth time and held the side of the blade to my try-square handle... with the blade being 58mm across, it moved away from the try-square blade by 1mm across it's width.
I know this method of measuring cannot give me great accuracy, but this comes to around 10 degrees by which the blade is not square on the cutting edge. I am simply not happy with that.
I called up the supplier and the manager told me about the lever which moves the blade from side to side, suggesting I use that to straighten the blade. That does not work, I have it moved over as far as possible and that corner still bites into the wood.
The manager suggested that I then tweak the blade 'skew' against the cap-iron, in order to get it straight at the mouth.
No way!!! ... If I buy a car, the dealership cannot expect me to crank the steering wheel all the way to the left .. in order for the car to drive straight!

I'm taking it back.
The manager did not sound to happy, and mumbled something about giving me something of equal value.
That's not going to work either.
I do not need anything else.
I do not want anything else.
... a plane ... a No 6 or a No 7 ... a decent working one ... that's what I want, or my money back.

In honesty, I could have fixed the stripped bolt problem. Although, being 'backwards' thread it would have cost a little bit extra to get a bolt.
I can also have the blade re-ground to 90 degrees at an engineering shop, or if I find a sharpening place... but you know, I just spent R595.00 on this plane. Why should I still need to go to all that trouble to fix it when it's brand new?

This will be the third trip to the center of town, 30km each way. Plus it's been helluva inconvenient.