what are my chances if I was charged with a dui but was never seen driving a vehicle
The government has to prove you were the driver, so that is always an issue. As for what your "chances" are depends on the overall circumstances, none of which you outline. If you have a lawyer then you should talk with him/her about this issue. Otherwise, feel free to contact me directly.
Craig Orent, Esq.
Orent Law Offices, PLC
11811 N. Tatum Blvd. Suite 3031
Phoenix, AZ 85028
480-656-7301
corent@orentlaw.com