It's a lovely little tank, but looking at your signature, it's a bit overstocked. The angels need a 29g minimum that's at least 18" high, and if those plecs are common plecs - you'll be looking at needing a 6ft x 2ft x 2ft for all three of them (or doing the wiser thing and returning them asap!). I'd return the angels and plecs, and stick with the others (although I do agree about the frog - they're not the best tank mates!).
For future reference, 9 times out of ten, you're better off listening to a carpet salesman than a fish shop employee

The majority (not all by a long shot - but the majority none the less) are only interested in making a sale. Anyone who sells three potentially 18" plecs to someone with an 84 litre tank though is obviously not a good starting point for information. Always research your fish
before you buy them - then you wont end up having to take any back!