Thanks for sharing more of the details. I don't think it has to do with the deposit because as mentioned, until there is signed paperwork, anyone can back out.
To me, it sounds like you called, made a full offer, and that offer never made it into the paperwork stage because you have not mentioned receiving contract--which you would have, either that day or the next one at most, even before the deposit needed to be in.
We have dealt with TSS as buyers and sellers and both times, we were emailed the contracts within hours of the verbal agreement and it sounds like this may not have happened--which could be why the other agents didn't know you had made the offer.