The 4900 cartridges have plastic "keys" attached, which are specific to the color position, and make it so a cart can only be installed into the position it's keyed for. Although it's very rare, we have found a few occasions where a cart doesn't have the correct key attached to match the chip and color position label. In this case, the wrong key can be removed and correct key attached.
I see you purchased two sets of 4900 refillable carts. Do you have two 4900 printers, or are you using one set of carts with PiezoFlush and the second with ink? If you're only using one set of carts, and have the other aside, then you can quickly/easily attach the key from one VM cart to the other.
Referring to the photo on the top/left (page 1) of our 4900 refill cartridge instructions, the key is located on the non-labeled side of the cartridge, in the notch between the exit valve and top of the cart. It is held in place with two small plastic points, and can be easily pried off. The color position of each key is part of the key mold, so is a small plastic letter code indicates which key goes to which color position cartridge.
Regarding your second problem, based on your order dates, I suspect you're dealing with old/worn out chip batteries, and recommend you replace the batteries. You can find information for replacing the batteries here: http://www.inkjetmall.com/wordpress/product-use/r3000-cartridge-batteries/
We have new batteries and replacement chips available here: http://shopping.netsuite.com/s.nl/c.362672/sc.18/category.84882/.f
I hope this helps. Please let me know if you have further questions or there's anything else I can help you with.
Best regards~ Dana