Yes,  i understand your query and worry about the lost registration slip. 

But dont worry if you have payment slip of your alloted college. 

Because if you have the print of payment slip then it is clear that you have registered, alloted with seat and payment is done because without registration you font have the payment slip as you are alloted with seat. 

Still you can print the registration slip simply by login into your id if you have done online or you can ask for registration slip if you need in offline counselling. 

But,  as per my say don't worry if you have printed payment slip because it is proof that you had done all steps of registration before then only payment slip is generated. 

Still if you have any query, you can ask in comments