Sumproduct formula - how to put the criteria together

There are a few formulas which I need help on but the first formula I need is to count invoices within the month but NOT if the word "refund" is displayed in the corresponding cells of column J (J18:J80) or if the word "Paid Acc." is displayed within this same data range (J18:J80)

I'm guessing the formula will be a sumproduct but I'm not familiar with these and have tried to play around with it but cannot seem to get a proper value returned.

The formula which is currently being used is a countif formula as follows:

=SUMPRODUCT((B18:B80<>"")*(J18:J80<>"PAID ACC."))

Any help would be grately appreciated.

Excellent thanks, this works.

I think I'm getting to grips more with sumproduct formulas now. Does the * within a formula split up the criteria? And also what does the two -- mean at the start of the formula? is this saying that there are multiple criteria within the formula?

Sorry, I didn't think that they were duplicate posts because at the time I didn't fully understand the sumproduct formula which was given to me. I'm currently reading through the websites you have given me to try and understand them more rather than just copying down functions from here without understanding why and how the function is written.

From playing around am I right in thinking that to add data which does not include a certain word or phrase you use the <> symbol?

i.e.

=SUMPRODUCT((E18:E70)*(J18:J70<>"Paid acc.")) this would only add up the cells which do not contain the word "paid acc."

whereas;

=SUMPRODUCT((E18:E70)*(J18:J70="Paid acc.")) would add up the cells which only contained the word "paid acc."

Can this rule be transferred to a sumif function?

I am currently using multiple sumif functions to add up all amounts which have been paid by either visa, mastercard, switch and maestro.

=SUMIF(I18:I76,"visa",E18:E121)+SUMIF(I18:I121,"m/card",E18:E121)+SUMIF(I18:I121,"maestro",E18:E121)+SUMIF(I18:I121,"switch",E18:E121)

I need to add another criteria so that it will only add these up aslong as "refund" is not displayed in J18:J121. I have tried to add another sumif using the <> but it does not seem to work and when I have tried to use the sumproduct function it is returning a £0.00 value as though it is looking for all the arrays within the same cell.

Any help or ideas would be greatly appreciated.