Well, if you have money on your tab you could pay out the remainder and start over with a newer phone. If the phone you have is toast that is. Another would be to possibly look on eBay and purchase a device for cheaper too. You have options it's your decision at the end of the day on what you want to do.
How much do you owe on your current tab? you have the option of paying that off and charging it to your next invoice as long as there is no past due balance for your monthly bill, or pay in store that day for the remaining tab. You can start a new tab with the phone you choose and have a brand new phone. You can also send it out for repair get a quote if its costs more then the current tab then you can decline repair, they will send back unrepaired and you can decide on what to do then. Also you can take it a local cell phone repair place in your area, you can probably google cellphone repair (your location) and something will come up and get a quote from them. Hope this helps :)