@Beeloux I'll do the maths for you.
In the UK, about half of women seeking abortions report that their contraception method failed, according to the BPAS. This means that nearly half of women undergoing abortions in the UK were using contraception at the time they became pregnant. Specifically, a study of women having abortions at BPAS clinics found that over half (51.2%) were using some form of contraception.
When that is broken down 17% comes from the pill, 38% condoms, 2% IUD, 1% implant 3% cap/diaphragm, 2% hormone injection, 1% sterilisation/vasectomy, 1% natural family planning, 1% MAP - the remaining ~% declined to answer.
251,377 is the total number of abortions in the UK in 2022 - that means approximately 12,568 women in the UK had an abortion that year whilst on long term birth control. (injection/iud/implant)
It simply isn't that rare and shocking that it could happen to people multiple times