Wobbly Print Bed on A20m

[msnively]

I just got the printer today, and out of the box the print bed wobbles left to right.
Two of the wheel's under the print bed don't even touch the rail it runs on. It looks like the holes for them were miss drilled.
I've contacted the seller of this unit via Amazon. I just wanted to know if this is a known issue, or just a one time thing?

[msnively]

Solved.

[davesatu]

For those who want to continue and know how to fix.
Underneath the bed you will see 4 nuts above the metal base.
Turn these anti-clockwise in turn until the bed is tight.
But warning - don't go too tight.
I know personally of 7 cases where the bed was delivered loose.
And where are the maker instructions?
NONE.