[souffle]

You need to clarify your genetics understanding.
Your female is a Sable. It's not a Sable umbrous as Sable is actually an Umbrous black eyed cream. So genetics will be eeUu or eeUU (either one or two umbrous genes - they look the same)
Your male is a banded BEC so ee with one banded gene (two gives a very wide band so assuming he has a normal sized band)
Neither of them can 'carry' the white belly gene because if they did they would be roans. Cream combined with white belly always roans so they would be sable roan and cream roan banded if they did so this is a safe mating in that respect.
Assuming they have no other genes carried (like cinnamon which is recessive) you will get the chance of Black eyed cream and Black eyed cream banded and Sable and Sable banded pups in the litter. If the female has two umbrous genes they will all be sable or sable banded.
The scent from the female during the cycle can be quite varied so don't judge whether she is pregnant on that basis. If she does not stand to mate there is a chance she is. I'd advise you not to keep trying her on a test mating every few days as this can stress them and cause them to resorb a pregnancy. Leave at least 8 days. Personally we just wait it out till pups are due at 16 days and if nothing then remate. Some will stand when pregnant so best give her time to establish the pregnancy. At 12 days she will start to show usually with hip bulges. You often need several matings before you get a pregnancy especially if it is early in the year and they are just starting to breed. Don't assume there is anything wrong just yet! You do need to watch out though for any signs of anything that is an issue as mated females can be more prone to developing womb infections. Please be absolutely sure you have a large vet fund available in case there is a problem with the pregnancy. A spay or stuck pup that needs an op can be very expensive. Breeding is not all lovely pups and is often heartbreak and loss. You also need housing for all the pups by 4 weeks of age and also for any you cannot home individually by 6 weeks really to be safe. Genders need separated by 4 weeks from mum. They eat a ton of food and extras and they need loads of time to tame and clean out.
Read over care of the female and check you pedigrees to see what you may get in the litter.