The Uniden TRU9XXX series has a high level of handset compatibility between bases. Depending on the handsets you bought to go with your
9480, you may be able to buy another model in the series and use the old handsets with the new model. Alternatively, you could
buy another 9480 here (the -2 on the end of your model number just means that it came with an extra handset).
Before you do that, though, it might pay to hook up a regular (corded) caller ID-enabled phone to the line and see what happens there when you call. If it works properly, go buy your new phone. However, if you see the same behavior there as with the Uniden, chances are that the problem is not with the phones. Possible other causes could include a fax machine, modem, or other device in-line with the phone; a defective piece of equipment hooked up elsewhere in your house; etc. If nothing obvious applies, you might want to give the phone company another call--just because they couldn't find a problem on their end doesn't mean one doesn't exist.