Sorry for the delay.
Your interpretation of what these people did or didn't see is not necessarily the same as theirs. They obviously feel that you acted suspiciously and they may be mistaking your unwillingness to cooperate with them as an indication of guilt.. Whether this will rise to the level of probable cause would be something that the police will determine if the store contacts them and once they tell their story.
Can people lie to get other people arrested? Yes, of course they can, and it does happen. However, more people are honest than not, and they are not inclined to make out false reports. If they do press charges, you could choose to fight the case all the way to trial to challenge what evidence they had or, if you wanted to make a deal, you could likely get one that would not only keep you out of jail but that won't brand you with a criminal record. If you are charged and win at trial, you may be able to recover something in civil court for the harassment and intimidation they are putting you through.
Ít's impossible for anyone here to read their minds and know whether they are going to call the police, but it does appear that they are watching you, and there may or may not be video information that would bolster their story or yours. So again, I would either avoid this store at this point or consider saving your receipts and showing them when asked.
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