Weird situation with student loan repayment

I am a former student from the EU who took out a loan to pay my tuition fees.

I graduated in 2011 but had to go home for a year but then returned last October to start my grad job in the UK.

During the time that I was away I had an income below the threshold and hence filled out my repayment exemption form i.e I would be reassessed for repayment in a year´s time (which is about now).
Anyway when I started my job I filled out a P46 form telling my employer to deduct the loan repayment from my salary and as of today, well over 300 pounds has been deducted from my monthly paychecks. However surprise surprise when I received a letter from the SLC recently asking me to provide details of my income. After logging into my account there seems to be no record of any repayments having come through.

This leads me to question: as money has clearly been deducted from my salary and paid to the HMRC/SLC, where has it gone if the SLC is not recognizing it as reducing my balance?
I will of course call the SLC come Monday (as their lines are closed on the weekends) but has anyone else had a situation like this or know what might be the cause of it?

I did of course start to wonder how the SLC would match the payments that my employer was making to my account since all they have to go on is a name and that isn´t always reliable.

I am a former student from the EU who took out a loan to pay my tuition fees.

I graduated in 2011 but had to go home for a year but then returned last October to start my grad job in the UK.

During the time that I was away I had an income below the threshold and hence filled out my repayment exemption form i.e I would be reassessed for repayment in a year´s time (which is about now).
Anyway when I started my job I filled out a P46 form telling my employer to deduct the loan repayment from my salary and as of today, well over 300 pounds has been deducted from my monthly paychecks. However surprise surprise when I received a letter from the SLC recently asking me to provide details of my income. After logging into my account there seems to be no record of any repayments having come through.

This leads me to question: as money has clearly been deducted from my salary and paid to the HMRC/SLC, where has it gone if the SLC is not recognizing it as reducing my balance?
I will of course call the SLC come Monday (as their lines are closed on the weekends) but has anyone else had a situation like this or know what might be the cause of it?

I did of course start to wonder how the SLC would match the payments that my employer was making to my account since all they have to go on is a name and that isn´t always reliable.