There have been claims that white slavery never happened, but there are contemporary accounts which suggest it was definitely a thing, though of course not on the scale of the African Trade.
The fact that it happened at all says much of the unsettled times especially in the mid 17th century, and treatment of the poor and vulnerable in various parts of Europe. White Prisoners of War were sent to the Caribbean colonies by Cromwell, both Royalist troops and of the many Irish captives, the descendants of whom survive in the Caribbean, and were known as redlegs. Scottish survivors from the Battle of Dunbar were shipped from Bristol to the plantations though many died of their injuries.
This is by John Esquemeling c.1645-1707), possibly a Huguenot, whose full name was Alexandre Olivier Exquemelin who was either French, Dutch or Flemish. His well written and detailed book was published in Dutch as De Ameriicaensche Zee-Rovers in 1678 and in English 1684. As with other accounts of the time, such as by Willliam Dampier and his colleagues, he records no incidents of outright criminal behaviour by the author, but the information is the best we can expect by a first hand observer at the time.
Tortuga In this country the planters have but very few slaves, for want of which they themselves, and some servants they have, are constrained to do all the drudgery. These servants commonly oblige and bind themselves to their masters for the space of 3 years. But their masters, forsaking all conscience and justice, oftentimes traffic with their bodies, as with horses at a fair; selling them to other masters, just as they sell Negroes brought from the coast of Guinea. Yea, to advance this trade some persons there are who go purposely into France (the same happens in England and other countries) and travelling through the cities, towns and villages, endeavour to pick up young men or boys, whom they transport, by making them great promises. These, being once allured and conveyed into the islands I speak of, they force to work like horses, the toil they impose upon them being much harder than what they usually enjoin on the Negroes, their slaves. For these they endeavour in some manner to preserve, as being their perpetual bond-men; but as for their white servants, they care not whether they live or die, seeing that they are to continue no longer than 3 years in their service. These miserable kidnapped people are frequently subject to a certain disease which in those parts is called coma, being a total deprivation of all their senses. And this distemper is judged to proceed from their hard usage, together with the change from their native climate into that which is directly opposite. Oftentimes it happens that, among these transported people, such are found as are persons of good quality and tender education. And these, being of a softer constitution, are more suddenly surprised with the disease above-mentioned and with several others belonging to those countries, than those who have harder bodies and have been brought up to all manner of fatigue. Besides the hard usage they endure in their diet, apparel and repose, many times they beat them so cruelly that some of them fall down dead under the hands of their cruel masters. This I have often seen with my own eyes, not without great grief and regret.