Sort products by price *BUG

[iRescue.gr]

Dear Sirs,
I have been using virtuemart for a long time and I have stumbled upon a lot of minor bugs. I found most solutions using the forum but this time I am not able to figure my way out of this problem.
Let's say we have a lot of products in a category and most of them have the same price. Let's also say that we must display only 3 products per page.
For example when sorting by product name we have the following result:
Page 1:
Product - Price
A - 10
B - 15
C - 10
Page 2:
Product - Price
D - 10
E - 10
F - 10

Now if we sort by price it should be something like this:
Page 1:
Product - Price
A - 10
C - 10
D - 10
Page 2:
Product - Price
E - 10
F - 10
B - 15

Now the exact problem is that because most of the products have the same price, different products may appear in each refresh.
And secondly, when you go to the second page of the pagination results, because the query is rerun you may see some products that you already saw in the previous page (leaving completely out of your view some other products). For example:
Page 1:
Product - Price
A - 10
C - 10
D - 10
Page 2:
Product - Price
C - 10
A - 10
B - 15

I hope I made myself clear about the issue and that there is a possible solution.
Best Regards,
George Angelopoulos