First of all there is the repair itself, but there isn’t any collection service so you need to travel (often a full day) to get to a repair centre. Then travel back. Not open on the weekend so you have to do it during the week, meaning you are also loosing 2 days of income. Then you have to go and get it once it’s done.
Total cost of repair for people using these devices might 10+ days worth of income if you include the opportunity cost.
That’s why we are training people to fix these systems within their communities.
Regarding parts you can get second life batteries in Kenya for $1-2 per cell from people like Acele Africa[1], so you can get total repair cost down to ~$10 (that’s ~3% of original purchase price)