Doing Your Own Checking. Another good thing to know is how much Credit you can use on a certain Card. This is where Creditell comes into action. If you are able to gain access to such a thing then the amount of things you can do is endless. Because you can run a Credit Check on any Credit Card. Section 5 Merchant Numbers. The next best thing to Creditell is a Merchant number. A Merchant number is the number that the shop quotes to Bankcard, Mastercard, Visia, American Express, Etc when they ring up to do a Credit Check from the shop it's self. I have two Merchant numbers one for a Bike Shop and one for a Resturant, the Resturant is the best one because it doesn't look strange if you ring up at 2 am.