Southwest LUV Vouchers - Can I use multiple of travel?
The max number of payment sources accepted online is 4. So, if you have a flight over $400, you can't easily do it yourself online (because the 4th payment source would have to have enough for the booking...like a CC). Since these were recently issued to you a Customer Relations agent may be able to combine 2 into a new voucher if you need to use all of them on one flight.